Quick Recipe Version (TL;DR)
Quick Ingredients
- 12 oz (340 g) penne or rotini pasta
- 2 cups (about 10 oz/280 g) cooked chicken, shredded or diced
- 2 cups (170 g) broccoli florets (optional) or 3 cups (90 g) baby spinach (optional)
- 4 tbsp (56 g) unsalted butter
- 4 garlic cloves, finely minced
- 3 tbsp (24 g) all-purpose flour
- 2 cups (480 ml) whole milk
- 1 cup (240 ml) heavy cream
- 1 1/2 cups (150 g) finely grated Parmesan, plus 2 tbsp for topping
- 1 1/2 tsp kosher salt, plus more for pasta water
- 1/2 tsp black pepper
- 1/8 tsp ground nutmeg (optional)
- 2 cups (200 g) shredded mozzarella
- 1 tbsp chopped fresh parsley (optional, for serving)
Do This
- 1. Heat oven to 375°F (190°C). Butter a 9×13-inch baking dish.
- 2. Boil pasta in well-salted water until 1 minute under al dente; drain.
- 3. Make Alfredo: melt butter, cook garlic 30 seconds, whisk in flour 1 minute.
- 4. Whisk in milk + cream; simmer 3–5 minutes until thick enough to coat a spoon. Stir in Parmesan, salt, pepper, nutmeg.
- 5. Toss pasta + chicken + broccoli/spinach with sauce; spread in dish.
- 6. Top with mozzarella (and extra Parmesan). Bake 15 minutes covered, then 10 minutes uncovered until browned; broil 2 minutes if needed.
- 7. Rest 10 minutes so it stays silky, then serve (parsley on top).
Why You’ll Love This Recipe
- Comfort-food creamy without tasting heavy or bland, thanks to garlic and Parmesan.
- Easy to assemble in one dish, perfect for weeknights or potlucks.
- Flexible: add broccoli for a hearty bite or spinach for a softer, greener twist.
- Bakes up with a browned, cheesy top while the inside stays rich and silky.
Grocery List
- Produce: garlic (4 cloves), broccoli florets (2 cups) or baby spinach (3 cups), fresh parsley (optional)
- Dairy: unsalted butter, whole milk, heavy cream, Parmesan cheese, shredded mozzarella
- Pantry: penne or rotini pasta, all-purpose flour, kosher salt, black pepper, ground nutmeg (optional)
- Protein: cooked chicken (or cook your own from boneless skinless chicken breasts or thighs)
Full Ingredients
Pasta & Add-Ins
- 12 oz (340 g) penne or rotini pasta
- 2 cups (170 g) broccoli florets, optional
- 3 cups (90 g) baby spinach, optional (use instead of broccoli)
Chicken
- 2 cups (about 10 oz/280 g) cooked chicken, shredded or diced
Creamy Garlic-Parmesan Alfredo Sauce
- 4 tbsp (56 g) unsalted butter, plus a little extra for the baking dish
- 4 garlic cloves, finely minced
- 3 tbsp (24 g) all-purpose flour
- 2 cups (480 ml) whole milk
- 1 cup (240 ml) heavy cream
- 1 1/2 cups (150 g) finely grated Parmesan cheese
- 1 1/2 tsp kosher salt
- 1/2 tsp freshly ground black pepper
- 1/8 tsp ground nutmeg, optional (small amount, big payoff)
Topping
- 2 cups (200 g) shredded mozzarella cheese
- 2 tbsp (10 g) finely grated Parmesan cheese (optional, for extra browning)
- 1 tbsp chopped fresh parsley (optional, for serving)
Step-by-Step Instructions
Step 1: Preheat the oven and prep the baking dish
Arrange an oven rack in the middle position. Preheat the oven to 375°F (190°C).
Lightly butter a 9×13-inch baking dish (or a similar 3-quart casserole dish). This helps with cleanup and keeps the edges from sticking.
Step 2: Cook the pasta just shy of al dente
Bring a large pot of water to a boil. Add enough salt that the water tastes pleasantly salty (a good guideline is 1 1/2 tbsp kosher salt for a large pasta pot).
Add 12 oz pasta and cook until it is 1 minute under al dente based on the package directions. The pasta will finish cooking in the oven, and this prevents a mushy bake.
Drain the pasta well and set aside.
Step 3: Prep the chicken and optional vegetables
If your chicken is already cooked, simply shred or dice it into bite-size pieces (you want about 2 cups).
If using broccoli, blanch it quickly so it stays bright and tender in the bake: add 2 cups broccoli florets to boiling water for 2 minutes, then drain well.
If using spinach, no pre-cooking is needed. Keep it ready to stir in; it will wilt from the hot sauce.
Step 4: Build the creamy garlic-Parmesan Alfredo sauce
In a large saucepan or deep skillet over medium heat, melt 4 tbsp unsalted butter. Add the minced garlic and cook for 30 seconds, stirring constantly, just until fragrant (avoid browning the garlic).
Sprinkle in 3 tbsp flour and whisk continuously for 1 minute to cook out the raw flour taste. The mixture will look like a smooth paste.
Slowly whisk in 2 cups whole milk, then whisk in 1 cup heavy cream. Keep whisking until smooth. Bring the sauce to a gentle simmer and cook for 3–5 minutes, stirring often, until it thickens enough to coat the back of a spoon.
Turn heat to low and stir in 1 1/2 cups grated Parmesan until melted and smooth. Season with 1 1/2 tsp kosher salt, 1/2 tsp black pepper, and 1/8 tsp nutmeg (optional). Taste and adjust seasoning if needed.
Step 5: Combine pasta, chicken, sauce, and greens
In a large bowl (or right in the pasta pot), combine the drained pasta, 2 cups cooked chicken, and the Alfredo sauce.
Stir in your optional vegetable:
For broccoli: fold in the drained broccoli florets.
For spinach: add 3 cups baby spinach and stir until it just begins to wilt in the warm sauce.
The mixture should look generously saucy. This is what helps the inside stay silky after baking.
Step 6: Assemble and top with mozzarella
Spoon the mixture into the prepared baking dish and spread it into an even layer.
Sprinkle 2 cups shredded mozzarella evenly over the top. If you like a slightly deeper golden finish, add 2 tbsp grated Parmesan over the mozzarella.
Step 7: Bake until bubbling and browned (without drying out)
Cover the dish with foil (tent it slightly so it doesn’t stick to the cheese).
Bake at 375°F (190°C) for 15 minutes. Then remove the foil and bake for 10 minutes, until the edges are bubbling and the top is starting to brown.
If you want a deeper golden top, broil on high for 1–2 minutes, watching closely the entire time to prevent scorching.
Step 8: Rest briefly, then serve
Let the Chicken Alfredo Bake rest for 10 minutes before serving. This short rest helps the sauce settle so it stays creamy and doesn’t run watery on the plate.
Finish with chopped parsley if you like, and serve hot.
Pro Tips
- Undercook the pasta by 1 minute: It finishes in the oven and stays pleasantly chewy instead of soft.
- Grate your own Parmesan if possible: Pre-grated cheese can contain anti-caking agents that make sauces slightly grainy.
- Keep the bake silky: The foil-on first stage heats everything through without drying the top; uncovering at the end browns the cheese.
- Prevent a split sauce: After adding Parmesan, keep the heat low and stir gently; boiling can make cheese sauces look oily.
- Make it extra garlicky: Add 1 additional minced clove of garlic, but keep the sauté short so it doesn’t turn bitter.
Variations
- Extra-crispy topping: Mix 1/2 cup (30 g) panko with 2 tbsp melted butter and sprinkle over the mozzarella before baking.
- Mushroom Alfredo Bake: Sauté 8 oz (225 g) sliced mushrooms in 1 tbsp butter until browned; stir in with the chicken.
- Spicy Chicken Alfredo: Add 1/4 tsp crushed red pepper flakes to the butter and garlic, and stir 1 tbsp hot sauce into the finished sauce.
Storage & Make-Ahead
Refrigerate: Cool leftovers, then cover and refrigerate for up to 4 days.
Reheat: For best texture, reheat covered in a 350°F (177°C) oven for 15–20 minutes until hot. If it looks thick, stir in 1–3 tbsp milk before reheating to bring back the creamy consistency. Microwave reheating works too; use medium power and stir halfway through.
Make-ahead (best method): Assemble the casserole (without baking), cover tightly, and refrigerate up to 24 hours. Bake covered at 375°F (190°C) for 25 minutes, then uncover and bake 10–15 minutes until bubbling and browned.
Freeze: Freeze tightly wrapped for up to 2 months. Thaw overnight in the fridge before baking. (Cream sauces can change texture slightly after freezing, but this one holds up well.)
Nutrition (per serving)
Approximate, based on 6 servings: Calories: 690; Protein: 41 g; Carbohydrates: 55 g; Fat: 35 g; Saturated Fat: 19 g; Fiber: 3 g (more with broccoli/spinach); Sugars: 6 g; Sodium: 980 mg.
