Instructions

• Preheat oven to 350°F (177°C). Line a 9×9" pan with foil or parchment and spray the lining with nonstick cooking spray.
• Place 4 ounces (113 g) unsweetened baking chocolate and ¾ cup (170 g) unsalted butter in a large microwave-safe bowl. Heat in 30-second increments, stirring between each, until fully melted and smooth (about 2 minutes total, depending on your microwave).
• Stir 1 ¾ cups (350 g) granulated sugar into the chocolate mixture until combined. Stir in the 3 large eggs until well mixed.
• Add 1 teaspoon vanilla extract, 2 tablespoons (10 g) unsweetened cocoa powder, and ½ teaspoon salt to the mixture and stir until smooth. Carefully stir in 1 cup (124 g) all-purpose flour until just combined; do not overmix.
• Pour the batter into the prepared pan and smooth the top. Bake for 28–35 minutes. Test by inserting a toothpick about 1 inch from the side of the pan — the brownies are done when the toothpick comes out with just a few moist crumbs.
• While the brownies bake, make the caramel: put ½ cup (100 g) granulated sugar in a small saucepan and heat over medium. Stir often, keeping sugar from climbing the sides of the pan. The sugar will melt, form clumps, and then become a smooth amber liquid.
• Once the sugar is fully melted, reduce the heat to medium-low and add 2 tablespoons (28 g) unsalted butter (sliced). Stir until the butter melts, then carefully add ⅓ cup (79 ml) heavy whipping cream and stir until the caramel is smooth. If the caramel solidifies when you add the cream, reduce heat to low and stir constantly until smooth.
• Remove the caramel from the heat and stir in ½ teaspoon vanilla extract and a pinch of salt. Transfer the caramel to a jar or heatproof container and let it cool while the brownies finish baking.
• When the brownies come out of the oven, let the pan sit on a wire rack for 5 minutes. Pour ¼ cup of the caramel sauce over the top and use a spatula to spread it toward the edges. Let the brownies cool completely in the pan before slicing (you can refrigerate them to speed cooling and to harden the caramel). Reserve the remaining caramel to drizzle over brownies before serving.
• Store leftover caramel in an airtight container in the refrigerator and reheat gently to thin before using. Store baked brownies tightly covered for up to 3 days at room temperature or freeze for up to one month. Optional: sprinkle coarse or kosher sea salt on top before serving.