Garlic Butter Chicken & Broccoli Casserole – Cozy, Flavorful, and Weeknight-Friendly

If you love simple comfort food with big flavor, this Garlic Butter Chicken & Broccoli Casserole will hit the spot. It’s creamy, cheesy, and full of garlicky butter goodness, but still balanced with plenty of broccoli. Everything bakes together into a bubbly, golden pan that feels like a hug.

It’s easy enough for a weeknight, yet satisfying enough to serve to friends or family. Best of all, the prep is straightforward and the ingredients are familiar.

Garlic Butter Chicken & Broccoli Casserole - Cozy, Flavorful, and Weeknight-Friendly

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Prep Time 15 minutes mins

Cook Time 30 minutes mins

Total Time 45 minutes mins

Servings 6 servings

Ingredients

  

• 1.5 pounds boneless, skinless chicken breasts, cut into 1-inch pieces
• 4 cups broccoli florets (fresh or frozen, thawed and well-drained)
• 3 tablespoons unsalted butter
• 4 cloves garlic, minced
• 2 tablespoons olive oil
• 1 small yellow onion, finely chopped
• 2 tablespoons all-purpose flour
• 1 cup low-sodium chicken broth
• 1 cup milk or half-and-half (for extra richness)
• 1 teaspoon Dijon mustard (optional, for depth)
• 1/2 teaspoon paprika
• 1/2 teaspoon dried thyme (or Italian seasoning)
• 1 cup shredded sharp cheddar cheese
• 1/2 cup grated Parmesan cheese
• Salt and black pepper, to taste
• 1 cup cooked rice or cooked small pasta (optional, for a heartier bake)
• 1/2 cup panko breadcrumbs (optional, for topping)
• Fresh parsley, chopped, for garnish

Instructions

 

• Preheat your oven to 375°F (190°C). Grease a 9x13-inch baking dish and set it aside.
• Season and sear the chicken. Pat the chicken dry and season with salt, pepper, and paprika. Heat 1 tablespoon olive oil in a large skillet over medium-high heat. Sear the chicken in two batches until just cooked through, about 4–5 minutes total per batch. Transfer to a bowl.
• Sauté the aromatics. In the same skillet, add the remaining olive oil and the butter. When the butter melts, add the onion and cook until soft, 3–4 minutes. Stir in the garlic and cook for 30 seconds until fragrant.
• Make the sauce. Sprinkle in the flour and cook, stirring, for 1 minute. Slowly whisk in the chicken broth, then the milk or half-and-half. Add Dijon (if using) and thyme. Simmer for 2–3 minutes until slightly thickened. Season with salt and pepper to taste.
• Add the cheeses. Remove from heat. Stir in the cheddar and half of the Parmesan until melted and smooth. This should be a pourable, creamy sauce.
• Prepare the broccoli. If using fresh broccoli, blanch in boiling salted water for 2 minutes, then drain well. If using frozen, make sure it’s thawed and patted dry to avoid watering down the sauce.
• Assemble the casserole. In the prepared dish, combine the chicken, broccoli, and cooked rice or pasta (if using). Pour the garlic butter cheese sauce over everything and gently toss to coat evenly.
• Top and bake. Mix the panko with the remaining Parmesan and a pinch of salt. Sprinkle over the top for crunch (optional). Bake uncovered for 18–22 minutes, until bubbling and lightly golden.
• Rest and serve. Let the casserole rest for 5 minutes. Garnish with chopped parsley. Taste and adjust salt and pepper if needed, then serve warm.

What Makes This Special

This casserole leans heavily on garlic butter to build flavor from the start. Instead of relying solely on canned soup, it uses a quick homemade sauce that tastes fresher and richer.

The chicken is quickly seared for a tender bite, while the broccoli stays bright and crisp-tender. It’s a one-pan style bake that’s both hearty and comforting without being heavy. The leftovers also store well, making it a great make-ahead or meal-prep option.

Ingredients

• 1.5 pounds boneless, skinless chicken breasts, cut into 1-inch pieces
• 4 cups broccoli florets (fresh or frozen, thawed and well-drained)
• 3 tablespoons unsalted butter
• 4 cloves garlic, minced
• 2 tablespoons olive oil
• 1 small yellow onion, finely chopped
• 2 tablespoons all-purpose flour
• 1 cup low-sodium chicken broth
• 1 cup milk or half-and-half (for extra richness)
• 1 teaspoon Dijon mustard (optional, for depth)
• 1/2 teaspoon paprika
• 1/2 teaspoon dried thyme (or Italian seasoning)
• 1 cup shredded sharp cheddar cheese
• 1/2 cup grated Parmesan cheese
• Salt and black pepper, to taste
• 1 cup cooked rice or cooked small pasta (optional, for a heartier bake)
• 1/2 cup panko breadcrumbs (optional, for topping)
• Fresh parsley, chopped, for garnish

How to Make It

1. Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish and set it aside.
2. Season and sear the chicken. Pat the chicken dry and season with salt, pepper, and paprika.

   Heat 1 tablespoon olive oil in a large skillet over medium-high heat. Sear the chicken in two batches until just cooked through, about 4–5 minutes total per batch. Transfer to a bowl.

3. Sauté the aromatics. In the same skillet, add the remaining olive oil and the butter.

   When the butter melts, add the onion and cook until soft, 3–4 minutes. Stir in the garlic and cook for 30 seconds until fragrant.

4. Make the sauce. Sprinkle in the flour and cook, stirring, for 1 minute. Slowly whisk in the chicken broth, then the milk or half-and-half.

   Add Dijon (if using) and thyme. Simmer for 2–3 minutes until slightly thickened. Season with salt and pepper to taste.

5. Add the cheeses. Remove from heat.

   Stir in the cheddar and half of the Parmesan until melted and smooth. This should be a pourable, creamy sauce.

6. Prepare the broccoli. If using fresh broccoli, blanch in boiling salted water for 2 minutes, then drain well. If using frozen, make sure it’s thawed and patted dry to avoid watering down the sauce.
7. Assemble the casserole. In the prepared dish, combine the chicken, broccoli, and cooked rice or pasta (if using).

   Pour the garlic butter cheese sauce over everything and gently toss to coat evenly.

8. Top and bake. Mix the panko with the remaining Parmesan and a pinch of salt. Sprinkle over the top for crunch (optional). Bake uncovered for 18–22 minutes, until bubbling and lightly golden.
9. Rest and serve. Let the casserole rest for 5 minutes.

   Garnish with chopped parsley. Taste and adjust salt and pepper if needed, then serve warm.

How to Store

• Refrigerator: Cool completely, then cover tightly. Store for up to 4 days.
• Freezer: For best texture, freeze before baking.

  Assemble the casserole (without the panko topping), wrap well, and freeze up to 2 months. Thaw overnight in the fridge, add topping, and bake as directed.

• Reheating: Reheat individual portions in the microwave in 45–60 second bursts, stirring if needed. For the whole pan, cover with foil and warm in a 325°F oven until hot, about 20–25 minutes.

Benefits of This Recipe

• Balanced comfort: It’s rich and cheesy without being overwhelming, thanks to the broccoli and homemade sauce.
• Meal-prep friendly: Holds up well for a few days and reheats nicely.
• Kid-approved flavors: Garlic butter, mild cheddar, and tender chicken are familiar and crowd-pleasing.
• Flexible: Works with rice, pasta, or even cauliflower rice for a lighter twist.
• One-pan bake: Minimal cleanup once it hits the oven.

Pitfalls to Watch Out For

• Watery casserole: Pat broccoli dry and avoid overcooking it before baking.

  Excess moisture can thin the sauce.

• Overcooked chicken: Sear just until done. It will finish gently in the oven, keeping it tender.
• Broken sauce: Add liquids slowly while whisking, and don’t boil hard after adding cheese. Gentle heat keeps the sauce smooth.
• Bland flavor: Taste the sauce and adjust salt, pepper, and Dijon.

  A little extra Parmesan can boost savoriness.

• Soggy topping: Add panko just before baking, and don’t cover during the bake if you want a crunchy top.

Recipe Variations

• Lighter version: Use 2% milk, reduce cheese by 1/3, and skip the panko. Add extra herbs and a squeeze of lemon to brighten.
• Low-carb: Swap rice or pasta for cauliflower rice. Reduce liquid slightly to avoid a thin sauce.
• Mushroom twist: Sauté 8 ounces sliced mushrooms with the onions for an earthier flavor.
• Bacon boost: Crisp 4 slices of bacon, crumble, and fold into the casserole.

  Use some bacon fat in place of olive oil for the aromatics.

• Spicy kick: Add red pepper flakes, cayenne, or a spoon of chili crisp to the sauce.
• Different cheeses: Try Gruyère for nuttiness, Monterey Jack for melt, or a blend of mozzarella and Parmesan for extra stretch.
• Gluten-free: Use a gluten-free flour blend for the roux, and choose GF pasta or rice. Swap panko for crushed GF crackers.
• Dairy-free: Use plant butter, unsweetened almond or oat milk, and a dairy-free cheese that melts well. Thicken with a cornstarch slurry instead of a flour roux.

FAQ

Can I use rotisserie chicken?

Yes.

Shred about 3 to 4 cups of cooked chicken and skip the searing step. Add it directly to the casserole with the broccoli and sauce, then bake as directed.

Do I have to pre-cook the broccoli?

Fresh broccoli benefits from a quick blanch so it stays bright and tender. If using frozen, thaw and drain well, then pat dry.

You can skip the blanch if your florets are small and you prefer a firmer bite.

What can I use instead of flour to thicken the sauce?

Use 1 tablespoon cornstarch mixed with 2 tablespoons cold milk or broth. Stir it into the simmering liquid and cook until thickened before adding cheese.

How do I prevent the cheese sauce from turning grainy?

Keep the heat moderate, add cheese off the heat, and stir until just melted. Avoid boiling after the cheese goes in.

Finely grating the cheese also helps it melt smoothly.

Can I assemble this ahead?

Yes. Assemble up to the topping, cover, and refrigerate for up to 24 hours. Add the panko just before baking and increase bake time by 5–10 minutes if starting from cold.

What sides go well with this casserole?

A simple green salad with lemony dressing, roasted carrots, or garlic bread pair nicely.

You can also serve it with extra steamed broccoli or a quick tomato-cucumber salad for freshness.

Is it okay to use chicken thighs?

Absolutely. Boneless, skinless thighs stay very juicy and work well here. Trim excess fat and sear as instructed for breasts.

How can I add more protein or fiber?

Stir in a can of white beans (drained and rinsed) or add cooked quinoa instead of rice.

Both options boost protein and fiber without changing the flavor much.

Wrapping Up

Garlic Butter Chicken & Broccoli Casserole is the kind of recipe that earns a spot in your regular rotation. It’s creamy, garlicky, and satisfying, with just enough greens to feel balanced. The steps are simple, the ingredients are flexible, and the result is a cozy dinner that makes everyone happy.

Keep it classic, or try a variation that suits your taste. Either way, you’ll have a warm, crowd-pleasing meal on the table with minimal fuss.