This casserole is the dinner I reach for when I want the comfort of lasagna without fussy layering or lengthy sauce making. It pulls together tender diced chicken, browned mushrooms, fragrant spices, and a jar of good Alfredo — all tucked between sheets of Parmesan folio and melted mozzarella. It bakes up bubbly and gives you eight generous portions with a golden top and a creamy interior.
I like this dish because it’s practical: you can use leftover roasted or rotisserie chicken, it assembles quickly, and it tolerates a few smart swaps if you need to. The flavors are straightforward — poultry seasoning and sage for depth, garlic powder for warmth, mushrooms for umami — and the structure is forgiving. Let it rest before cutting so the layers firm up and slices stay tidy.
Below I break the recipe down into ingredients and steps you can follow precisely, plus tips to troubleshoot, swap ingredients, and store leftovers. Read the quick step-by-step if you want to get straight into the kitchen, or skim the notes to tailor the casserole to your family’s preferences.
Ingredient Breakdown
Ingredients
- 1 lb. mushrooms, chopped into medium-size pieces — provide meaty texture and savory depth; brown them well to concentrate flavor.
- 1 T + 2 tsp. olive oil — used for sautéing mushrooms and onions; split between initial browning and softening the onion.
- 8 cups diced, cooked chicken (see notes) — the protein backbone; rotisserie chicken works great for time-saving.
- 1 small onion, chopped — softens and sweetens when cooked; don’t skip for balance.
- 2 tsp. Poultry Seasoning — gives classic herby chicken flavor; mixes well with sage and garlic powder.
- 2 tsp. garlic powder — boosts savory notes without adding fresh garlic’s bite; easy to distribute.
- 1 tsp. dried sage (sometimes called rubbed sage; more or less to taste) — adds aromatic warmth and pairs naturally with chicken.
- one 15 oz. jar Rao’s Alfredo Sauce — the creamy sauce that binds everything; a good-quality jar saves time and delivers reliable texture.
- 4 Parmesan Cheese Folios, cut in half — act like lasagna sheets here; they crisp slightly and hold the layers together.
- 3 cups grated Mozzarella cheese — melts into a stretchy, golden top; divides between layers for even coverage.
Step-by-Step: Chicken Alfredo Lasagna Casserole
- Preheat oven to 375°F (190°C). Spray a casserole or lasagna dish (about 7.5″ x 11.5″ x 3″ if available) with non-stick spray.
- Chop 1 lb. mushrooms into medium-size pieces and chop the small onion. Have 8 cups diced, cooked chicken ready.
- Heat 1 tablespoon of the olive oil in a large frying pan over medium-high heat. Add the mushrooms and cook until they are nicely browned and any released liquid has evaporated, about 6–8 minutes. Transfer mushrooms to a plate.
- Add the chopped onion to the pan. If the pan is dry, add the remaining 2 teaspoons of olive oil. Cook the onion about 3 minutes, until softened.
- Sprinkle in 2 tsp poultry seasoning, 2 tsp garlic powder, and 1 tsp dried sage. Cook, stirring, 1–2 minutes to bloom the spices.
- Return the cooked mushrooms to the pan and add the 8 cups diced cooked chicken. Gently stir to combine.
- Pour in the 15 oz jar of Rao’s Alfredo Sauce and stir. Reduce heat to low and simmer about 10 minutes, stirring occasionally, until the sauce has thickened slightly.
- Cut the 4 Parmesan Cheese Folios in half. Arrange enough folio halves in a single layer to cover the bottom of the prepared dish, placing the straight edges along the sides.
- Spread half of the chicken–mushroom–alfredo mixture evenly over the folio layer.
- Sprinkle 1 1/2 cups grated mozzarella evenly over the chicken layer.
- Add another layer of folio halves to cover the cheese, then spread the remaining chicken–mushroom–alfredo mixture evenly over that layer. Top with the remaining 1 1/2 cups grated mozzarella.
- Bake uncovered at 375°F (190°C) for 30–35 minutes, until the casserole is bubbling hot and the top is lightly browned.
- Let the casserole rest about 10 minutes before cutting into eight pieces.
The Upside of Chicken Alfredo Lasagna Casserole
This casserole scores high on convenience and comfort. You get lasagna-style layers without rolling sheets or making a béchamel from scratch. Time-wise, the longest active parts are browning the mushrooms and a short simmer to thicken the sauce; the oven does the rest.
It scales easily: make a double batch for a potluck or halve it for two. It’s also forgiving about protein sources — leftover turkey, roasted chicken, or even a mix of shredded meats work. The assembly is modular, so kids can help layer, and it reheats well, which makes it a practical weeknight winner.
Easy Ingredient Swaps
- Chicken — leftover roasted or rotisserie chicken is a direct swap for the recipe’s diced, cooked chicken.
- Mushrooms — if you prefer vegetables with lighter texture, baby spinach or chopped zucchini can replace mushrooms; add spinach late so it wilts but doesn’t become soggy.
- Rao’s Alfredo Sauce — any good-quality jarred Alfredo works; if you have a favorite brand, use that instead.
- Parmesan Folios — if you can’t find folios, oven-safe lasagna noodles or no-boil sheets will work; expect slightly different texture.
- Mozzarella — provolone or a mild Monterey Jack can work in a pinch for a different melting profile.
Hardware & Gadgets
- Large frying pan — for browning mushrooms and softening onions; a 10–12-inch skillet is ideal.
- Casserole or lasagna dish (~7.5″ x 11.5″ x 3″) — the recipe assumes this size for layer fit and bake time.
- Measuring spoons — for the poultry seasoning, garlic powder, and sage.
- Spatula or wooden spoon — for gentle folding of chicken and mushrooms into the sauce.
- Box grater — if you grate fresh mozzarella for better melting and texture.
Missteps & Fixes
- Too watery chicken mixture after simmering — simmer a few extra minutes over low heat, uncovered, to reduce and thicken the sauce before assembling.
- Parmesan folios soggy in the center — make sure the sauce isn’t overly thin; if using a different sauce or extra-juicy chicken, drain excess liquid or briefly thicken on the stovetop.
- Top browns too quickly — tent the casserole loosely with foil for the first 20 minutes of baking, then remove foil to finish browning.
- Slices fall apart when served — let the casserole rest the full 10 minutes after baking so the layers set; cut with a sharp knife and use a wide spatula to lift pieces.
Seasonal Flavor Boosts
- Autumn — stir in a few tablespoons of roasted butternut squash cubes to the chicken mix for sweetness and texture contrast.
- Winter — add a pinch more dried sage and a few grinds of black pepper for cozy, warming notes.
- Spring — fold in a handful of chopped fresh parsley or basil after the casserole rests to brighten the dish.
- Summer — top individual servings with a squeeze of lemon or a light drizzle of olive oil and fresh basil to bring freshness.
Recipe Notes & Chef’s Commentary
Use the best jarred Alfredo you can find; a quality sauce keeps this recipe quick but flavorful. Rao’s is the referenced brand here because it maintains body and flavor when baked, but any reliable jar will do.
Brown the mushrooms thoroughly. That step adds a concentrated, savory backbone to the casserole. If the mushrooms release a lot of liquid, keep cooking them until the pan is nearly dry before transferring them off — it makes a noticeable difference.
If you prefer a more pronounced herb profile, increase the sage slightly, but add it sparingly — sage can overwhelm. Poultry seasoning and garlic powder are the steady flavors; they should taste familiar, not bold.
Best Ways to Store
Cool the casserole to room temperature, then cover tightly and refrigerate for up to 3 days. For longer storage, cut into portions and freeze in airtight containers or heavy-duty freezer bags for up to 2 months. Label with the date and reheating instructions.
To reheat from the fridge: place a portion in an oven-safe dish, cover with foil, and bake at 350°F (175°C) until heated through, about 15–20 minutes. To reheat from frozen: thaw overnight in the refrigerator if possible, then bake covered at 350°F until hot; if baking from fully frozen, add time and keep covered to prevent over-browning.
Chicken Alfredo Lasagna Casserole Q&A
- Can I make this ahead? — Yes. Assemble the casserole up to 24 hours in advance, cover, and refrigerate. Bake directly from chilled; you may need an extra 5–10 minutes.
- Can I use fresh garlic instead of garlic powder? — You can, but since directions use garlic powder, use one to two cloves finely minced and sauté with the onion so the raw edge mellows.
- Is there a vegetarian version? — Replace the chicken with extra vegetables, tofu, or a plant-based chicken substitute and proceed the same way.
- Do the Parmesan folios need pre-cooking? — No. They’re layered as-is in this casserole and bake in the dish.
Ready, Set, Cook
Gather your ingredients, preheat the oven, and brown those mushrooms first — that step sets the tone. If you’re using leftover chicken, dice it into even pieces for consistent bites. Assemble in the dish, top with mozzarella, and bake until bubbly and lightly browned. Let it rest, slice into eight, and serve with a simple green salad or roasted vegetables.
Make this once and you’ll see how well it holds up for busy nights and casual gatherings. It’s comfort food done efficiently, so you spend less time at the stove and more time at the table.
Chicken Alfredo Lasagna Casserole
Equipment
- Oven
- casserole or lasagna dish (about 7.5" x 11.5" x 3")
- non-stick spray
- Large frying pan
- Plate
Ingredients
Ingredients
- 1 lb. mushrooms chopped into medium-size pieces
- 1 T + 2 tsp. olive oil
- 8 cups diced cooked chicken (see notes)
- 1 small onion chopped
- 2 tsp. Poultry Seasoning
- 2 tsp. garlic powder
- 1 tsp. dried sage sometimes called rubbed sage; more or less to taste
- one 15 oz. jar Rao's Alfredo Sauce
- 4 Parmesan Cheese Folios cut in half
- 3 cups grated Mozzarella cheese
Instructions
Instructions
- Preheat oven to 375°F (190°C). Spray a casserole or lasagna dish (about 7.5" x 11.5" x 3" if available) with non-stick spray.
- Chop 1 lb. mushrooms into medium-size pieces and chop the small onion. Have 8 cups diced, cooked chicken ready.
- Heat 1 tablespoon of the olive oil in a large frying pan over medium-high heat. Add the mushrooms and cook until they are nicely browned and any released liquid has evaporated, about 6–8 minutes. Transfer mushrooms to a plate.
- Add the chopped onion to the pan. If the pan is dry, add the remaining 2 teaspoons of olive oil. Cook the onion about 3 minutes, until softened.
- Sprinkle in 2 tsp poultry seasoning, 2 tsp garlic powder, and 1 tsp dried sage. Cook, stirring, 1–2 minutes to bloom the spices.
- Return the cooked mushrooms to the pan and add the 8 cups diced cooked chicken. Gently stir to combine.
- Pour in the 15 oz jar of Rao's Alfredo Sauce and stir. Reduce heat to low and simmer about 10 minutes, stirring occasionally, until the sauce has thickened slightly.
- Cut the 4 Parmesan Cheese Folios in half. Arrange enough folio halves in a single layer to cover the bottom of the prepared dish, placing the straight edges along the sides.
- Spread half of the chicken–mushroom–alfredo mixture evenly over the folio layer.
- Sprinkle 1 1/2 cups grated mozzarella evenly over the chicken layer.
- Add another layer of folio halves to cover the cheese, then spread the remaining chicken–mushroom–alfredo mixture evenly over that layer. Top with the remaining 1 1/2 cups grated mozzarella.
- Bake uncovered at 375°F (190°C) for 30–35 minutes, until the casserole is bubbling hot and the top is lightly browned.
- Let the casserole rest about 10 minutes before cutting into eight pieces.
