These brownies live at the intersection of two things everyone loves: dense, fudgy chocolate and that salty-sweet hit of peanut butter. They’re flourless, so the texture is rich and truffle-like rather than cakey. If you want a dessert that feels indulgent but is straightforward to make, this is it.

The method is forgiving: melt, whisk, bake, cool, and finish with two simple drizzles. There’s no sifting of flour, no temperamental folding. You’ll use the microwave for melting, the oven for a precise bake, and patience for the cooling and chilling steps that make the bar-set properly.

I test and retest recipes so I can tell you what matters and what doesn’t. Read through the ingredient notes, follow the step-by-step directions exactly, and give the brownies the recommended chill time. Do that and you’ll get clean slices with glossy chocolate and peanut-butter ribbons every time.

Ingredients at a Glance

½ cup unsalted butter (1 stick) — provides the fat that gives the brownies their glossy, fudgy texture; use unsalted to manage salt level.
2 cups semi-sweet chocolate chips (one 12-ounce bag) — the primary chocolate for the batter; melt with butter for a smooth base.
heaping 1/2 cup creamy peanut butter — folded into the melted chocolate for flavor and density; choose a creamy style for smoothness.
2 tablespoons brewed coffee — enhances chocolate depth; leftover morning coffee is fine; water may be substituted.
4 large eggs — the sole structural component in a flourless brownie; they set the batter as it bakes.
⅓ cup granulated sugar — sweetens and helps with the shiny, fudgy crumb; do not skip.
1 tablespoon vanilla extract — balances and rounds the chocolate and peanut butter.
⅓ cup unsweetened natural cocoa — adds chocolate intensity without extra sugar; whisk in thoroughly to avoid lumps.
1 teaspoon instant espresso granules (optional) — amps up chocolate flavor without tasting like coffee; recommended but optional.
½ cup semi-sweet chocolate chips — for the chocolate drizzle finishing the cooled brownies.
⅓ cup creamy peanut butter — warmed for drizzling on top after the chocolate drizzle.

Peanut Butter and Chocolate Flourless Brownies: From Prep to Plate

Preheat oven to 300°F. Line a 9×9-inch pan with foil, leaving an overhang for easy removal, and spray the foil with cooking spray. Set the pan aside.
Put ½ cup unsalted butter (1 stick) in a large microwave-safe bowl. Microwave on high for 1 minute. If the butter is not fully melted, continue heating in 10-second bursts, stirring after each, until melted.
Add 2 cups semi-sweet chocolate chips, a heaping 1/2 cup creamy peanut butter, and 2 tablespoons brewed coffee to the bowl with the melted butter. Microwave on high for 1 minute, then stir. If the chocolate and peanut butter are not fully melted and smooth, heat in 10-second bursts, stirring between each burst, until the mixture is smooth and pourable.
Whisk the melted chocolate mixture until uniform and glossy.
Add 4 large eggs, ⅓ cup granulated sugar, and 1 tablespoon vanilla extract to the chocolate mixture. Whisk until the eggs and sugar are fully incorporated and the batter is smooth.
Add ⅓ cup unsweetened natural cocoa and 1 teaspoon instant espresso granules (optional). Whisk until the cocoa and espresso granules are fully incorporated and the batter is smooth with no lumps.
Pour the batter into the prepared 9×9 pan and smooth the top lightly with a spatula.
Bake about 35 minutes, or until the edges are set and the top and center have just set (not jiggly). A toothpick inserted in the center should come out with a few moist crumbs but no wet batter.
Remove the pan from the oven and place it on a wire rack. Let the brownies cool completely in the pan, at least 2 hours, before adding the drizzles.
When the brownies are completely cool, place ½ cup semi-sweet chocolate chips in a small microwave-safe bowl. Microwave on high about 1 minute, then stir. If not fully melted and smooth, heat in 10-second bursts, stirring between, until smooth and pourable. Drizzle the melted chocolate over the cooled brownies using a spoon or squirt bottle.
Place ⅓ cup creamy peanut butter in a small microwave-safe bowl. Microwave on high about 45 seconds, then stir. If not pourable, heat in 10-second bursts, stirring between, until smooth. Drizzle the warmed peanut butter over the chocolate drizzle.
Cover the pan with foil to prevent fridge odors and chill the brownies in the refrigerator at least 4 hours, or preferably overnight, before serving.

Why This Recipe Is Reliable

Flourless brownies rely on eggs and chocolate for structure rather than flour. That makes precision with temperature and timing more important than with a typical brownie. The low oven temperature and the 35-minute bake time coax the eggs to set slowly, creating a fudgy interior instead of a dry crumb.

The melting sequence—butter, chocolate chips, peanut butter, coffee—creates a cohesive, glossy base. Whisking until smooth ensures there are no streaks of unmelted chocolate or peanut butter. The espresso granules are optional but recommended: they deepen the chocolate profile without adding a coffee taste.

Cooling fully and then chilling (the long fridge time) is non-negotiable. These bars finish firm, slice cleanly, and hold the drizzles without sliding when they’ve had time to set.

Healthier Substitutions

If you want to nudge this recipe toward lighter choices without changing its essence, here are careful options that keep the core ingredients:

Use a natural-style creamy peanut butter instead of a more processed variety; this shifts fat composition slightly while preserving flavor and texture.
Swap the semi-sweet chocolate chips for a lower-sugar, higher-cocoa-percentage chip if you prefer less sweetness. Be mindful that darker chips can be more bitter.
Replace the 2 tablespoons brewed coffee with the suggested water substitution if you’re avoiding caffeine; the coffee primarily intensifies chocolate flavor and isn’t detectable as coffee.
Trim the drizzle amounts at the end (use less of the ½ cup chocolate chips or the ⅓ cup peanut butter) to reduce added sugar and fat without altering the batter.

Tools & Equipment Needed

9×9-inch baking pan; foil for lining and an overhang for removal.
Microwave-safe bowls (one large for melting, two small for drizzles).
Whisk and spatula for mixing and smoothing the batter.
Measuring cups and spoons for accuracy.
Oven set to 300°F and an oven mitt or two.
Wire rack for cooling and a spoon or squirt bottle for drizzling.
Refrigerator space where the pan can sit flat and undisturbed for at least 4 hours.

Avoid These Mistakes

Overheating chocolate in the microwave. Heat in short bursts and stir well between bursts. Residual heat finishes the melt.
Skipping the cooling step. Drizzles and slices work only after the brownies cool completely and then chill.
Baking at a higher temperature. These are baked low and slow; increasing the oven temp will dry them out and change the texture.
Assuming doneness by time alone. Use the toothpick check described in the directions—moist crumbs, no wet batter.
Not lining the pan. The foil overhang makes removal and clean slicing far easier.

Nutrition-Minded Tweaks

Small procedural tweaks trim calories or sugar without changing the overall method:

Reduce the surface drizzles: halve the chocolate or peanut-butter drizzle to cut added fat and sugar after the bake.
Slice into smaller squares—smaller portions satisfy without large calorie hits, especially since these are rich and dense.
Use a higher-cocoa, lower-sugar chip for both the batter and the drizzle to reduce sugar intake per serving.

Method to the Madness

Why the microwave? It’s fast and efficient for melting chocolate and butter when you stir frequently in short bursts. The idea is to avoid overheating, which causes chocolate to seize. Stirring until glossy ensures an even emulsion of butter, chocolate, and peanut butter.

Whisking the eggs with sugar and vanilla into the warm chocolate mixture creates a smooth batter; the warmth helps dissolve the sugar and blend the eggs without scrambling. Adding the cocoa and espresso at the end gives chocolate depth and a concentrated cocoa note.

The long cooling and chill steps do two things: they let the internal temperature equilibrate so the center finishes setting, and they firm up the drizzles so the bars cut neatly. Rushing those stages results in smeared toppings and squishy slices.

Storing Tips & Timelines

Follow the recipe’s instruction to refrigerate for at least 4 hours, preferably overnight. Once chilled, cover the pan or wrap slices well to prevent odor transfer. Stored in the refrigerator, the brownies will keep for up to 5 days.

For longer storage, cut into squares and wrap each tightly with plastic wrap, then freeze in an airtight container for up to 2 months. Thaw wrapped in the refrigerator overnight, then bring to room temperature for 20–30 minutes before serving if you prefer a softer texture.

Your Top Questions

Can I skip the espresso? Yes. The 1 teaspoon instant espresso granules are optional and recommended only for depth; omitting them won’t affect structure.
Why do I need to chill for so long? The long chill time allows the dense, flourless batter to fully set and the drizzles to firm up so you can slice cleanly.
Can I make these ahead? Yes. They benefit from an overnight chill and will keep refrigerated for several days, making them great for planning ahead.
What if my chocolate seizes while melting? Stop heating. Stir vigorously; if needed, add a small splash of warm coffee (or water as the recipe allows) and stir until smooth. Heat only in short bursts after that.
How do I get clean slices? Use the foil overhang to lift the whole slab from the pan. Chill well, then use a sharp knife wiped between cuts, or warm the knife briefly under hot water and dry it before slicing.

In Closing

This is a practical, crowd-pleasing flourless brownie—intensely chocolatey, peanut-butter-forward, and reliably fudgy when you follow the key steps. The microwave melting, careful whisking, low-temperature bake, and patient chilling are the simple rules that deliver consistent results.

Make the batter, bake gently, chill overnight if you can, and slice with confidence. These brownies hold up well for events and keep in the fridge, so they’re a good make-ahead choice. Enjoy the glossy chocolate and peanut-butter ribbons—worth the wait.

Peanut Butter and Chocolate Flourless Brownies

Rich flourless brownies made with melted chocolate and peanut butter, finished with chocolate and peanut butter drizzles and chilled until set.

Print Recipe Save it

Prep Time 15

Cook Time 35

Total Time 2 50

Course Dessert

Servings 9 servings

Equipment

9x9 inch pan
Foil
Cooking spray
Large microwave-safe bowl
small microwave-safe bowls
Whisk
Spatula
Wire Rack
spoon or squirt bottle

Ingredients

1/2 cupunsalted butter 1 stick
2 cupsone 12-ounce bag semi-sweet chocolate chips
heaping 1/2 cup creamy peanut butter
2 tablespoonsbrewed coffee leftover from the morning is fine; does not make brownies taste like coffee, water may be substituted
4 large eggs
1/3 cupgranulated sugar
1 tablespoonvanilla extract
1/3 cupunsweetened natural cocoa
1 teaspooninstant espresso granules optional but recommend (does not make brownies taste like coffee)
1/2 cupsemi-sweet chocolate chips
1/3 cupcreamy peanut butter

Instructions

Preheat oven to 300°F. Line a 9×9-inch pan with foil, leaving an overhang for easy removal, and spray the foil with cooking spray. Set the pan aside.
Put ½ cup unsalted butter (1 stick) in a large microwave-safe bowl. Microwave on high for 1 minute. If the butter is not fully melted, continue heating in 10-second bursts, stirring after each, until melted.
Add 2 cups semi-sweet chocolate chips, a heaping 1/2 cup creamy peanut butter, and 2 tablespoons brewed coffee to the bowl with the melted butter. Microwave on high for 1 minute, then stir. If the chocolate and peanut butter are not fully melted and smooth, heat in 10-second bursts, stirring between each burst, until the mixture is smooth and pourable.
Whisk the melted chocolate mixture until uniform and glossy.
Add 4 large eggs, ⅓ cup granulated sugar, and 1 tablespoon vanilla extract to the chocolate mixture. Whisk until the eggs and sugar are fully incorporated and the batter is smooth.
Add ⅓ cup unsweetened natural cocoa and 1 teaspoon instant espresso granules (optional). Whisk until the cocoa and espresso granules are fully incorporated and the batter is smooth with no lumps.
Pour the batter into the prepared 9×9 pan and smooth the top lightly with a spatula.
Bake about 35 minutes, or until the edges are set and the top and center have just set (not jiggly). A toothpick inserted in the center should come out with a few moist crumbs but no wet batter.
Remove the pan from the oven and place it on a wire rack. Let the brownies cool completely in the pan, at least 2 hours, before adding the drizzles.
When the brownies are completely cool, place ½ cup semi-sweet chocolate chips in a small microwave-safe bowl. Microwave on high about 1 minute, then stir. If not fully melted and smooth, heat in 10-second bursts, stirring between, until smooth and pourable. Drizzle the melted chocolate over the cooled brownies using a spoon or squirt bottle.
Place ⅓ cup creamy peanut butter in a small microwave-safe bowl. Microwave on high about 45 seconds, then stir. If not pourable, heat in 10-second bursts, stirring between, until smooth. Drizzle the warmed peanut butter over the chocolate drizzle.
Cover the pan with foil to prevent fridge odors and chill the brownies in the refrigerator at least 4 hours, or preferably overnight, before serving.

Notes

Notes
Storage:
Brownies will keep airtight in the refrigerator for up to 7 days.