Some dinners are good because they’re quick. Others are good because everyone at the table actually wants seconds.
This Low Carb Chicken Broccoli Alfredo Bake is both.

Imagine tender pieces of seasoned chicken, fresh broccoli, and a rich, creamy Alfredo sauce coming together under a golden blanket of melted mozzarella and Parmesan. There’s no pasta hiding underneath, but you won’t feel like anything is missing.

Instead of filling the casserole with noodles, we’re using broccoli as the star vegetable and building the dish around protein-rich chicken and a creamy Alfredo sauce. It’s the kind of keto chicken broccoli casserole that feels like classic comfort food while fitting easily into a low-carb dinner plan.

The competitor recipes show two particularly useful approaches: one uses cauliflower rice to add bulk alongside broccoli, while another blends cottage cheese into the Alfredo mixture for an extra protein boost.
For this version, we’re keeping the best parts of both ideas while making the process straightforward.

The chicken gets browned first so it develops more flavor instead of simply being thrown into the casserole raw. The broccoli is cooked just enough to become tender without turning mushy. Then everything gets coated in creamy Alfredo sauce and topped with plenty of cheese.
After baking, the edges become bubbly and golden while the center stays creamy.

It’s perfect for a busy weeknight, Sunday meal prep, or those evenings when you want something warm and filling without reaching for a box of pasta.
If you’ve been searching for low-carb chicken Alfredo, chicken broccoli Alfredo casserole, keto chicken casserole, or a high-protein low-carb dinner, put this one on your list.

Why You’ll Love This Recipe

• ​One-Pan Comfort Convenience: Everything bakes together in a single casserole dish, making cleanup remarkably fast and easy.
• ​Loaded with Protein and Greens: Hearty chicken breasts and nutrient-dense broccoli keep you completely full and satisfied.
• ​Naturally Low-Carb and Grain-Free: Completely skips traditional pasta and flour thickeners without sacrificing any rich, velvety flavor.
• ​Kid-Approved Cheesy Flavor: The combination of melted mozzarella and sharp parmesan makes eating vegetables completely effortless for picky eaters.
• ​Meal Prep Friendly: Freezes and reheats brilliantly, making it an ideal choice for weekly lunch containers.

​Key Ingredients

Make Creamy Homemade Alfredo Sauce

• ​Boneless Skinless Chicken Breasts: Provides lean protein to make the entire casserole filling substantial.
• ​Fresh Broccoli Florets: Adds crisp texture, bright color, and essential healthy vegetable fiber.
• ​Unsalted Butter: Infuses traditional buttery richness and authentic Italian cooking flavor notes.
• ​Fresh Garlic Cloves: Sautéed in butter to deliver deep, savory, aromatic flavor notes.
• ​Shredded Mozzarella Cheese: Creates a bubbly, golden-brown cheese crust on top of everything.
• ​Italian Seasoning: Spices the dish with classic oregano, basil, and thyme notes.
• ​Salt and Black Pepper: Enhances all the natural flavors while balancing rich cheese fats.

​How to Make It: Step-by-Step Instructions

​Step 1: Preheat and Prep the Oven

​Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch glass or ceramic baking dish with butter or avocado oil spray to prevent sticking.

​Step 2: Cook the Chicken Breasts

​Season 1.5 pounds of boneless, skinless chicken breasts with salt, black pepper, and 1/2 teaspoon of Italian seasoning. Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Sear the chicken for 5 to 6 minutes per side until golden brown and cooked through (internal temperature reaches 165°F). Remove the chicken from the skillet, let it rest for 5 minutes, and cut it into bite-sized cubes.

​Step 3: Blanch the Broccoli Florets

​Cut 4 cups of fresh broccoli crowns into bite-sized florets. Bring a large pot of salted water to a boil, drop the broccoli in, and boil for exactly 2 minutes. Drain the broccoli immediately and rinse under cold running water to stop the cooking process and lock in the vibrant green color. Pat dry with paper towels.

​Step 4: Build the Alfredo Sauce

​Step 5: Melt in the Parmesan

​Reduce the heat to low. Stir in 1.5 cups of freshly grated Parmesan cheese, 1/2 teaspoon of Italian seasoning, 1/4 teaspoon of salt, and 1/4 teaspoon of black pepper. Whisk constantly until the sauce thickens into a glossy, smooth Alfredo coating.

​Step 6: Combine Chicken, Broccoli, and Sauce

​Add the cubed chicken and blanched broccoli directly into the skillet with the warm Alfredo sauce. Toss gently with a silicone spatula until every piece of chicken and broccoli is thoroughly coated in the cheesy sauce.

​Step 7: Transfer and Top with Mozzarella

​Pour the chicken and broccoli mixture into your prepared 9×13-inch baking dish, spreading it out into an even layer. Sprinkle 2 cups of shredded mozzarella cheese evenly over the top of the casserole.

​Step 8: Bake Until Bubbly

​Bake uncovered at 375°F for 20 to 25 minutes. During the last 3 minutes, switch your oven to broil to turn the mozzarella top layer deep golden brown and crispy. Let cool for 10 minutes before serving!

​Storage

• ​To Store: Allow the casserole to cool down completely to room temperature. Cover the baking dish tightly with aluminum foil or transfer individual portions into airtight glass containers. Store in the refrigerator for up to 4 days.
• ​To Freeze: You can freeze baked or unbaked portions of this casserole. Wrap tightly in plastic wrap and foil, then freeze for up to 3 months. Thaw overnight in the refrigerator before reheating.
• ​To Reheat: Warm leftovers in a preheated oven at 350°F (175°C) for 15 minutes, or microwave individual portions on medium power for 2 minutes until heated through.

​Frequently Asked Questions

​Can I use frozen broccoli instead of fresh?

​Yes, but you must thaw and squeeze out all excess moisture thoroughly using a clean kitchen towel. Frozen broccoli holds a lot of water, which can water down your Alfredo sauce if not dried first.

​Why did my Alfredo sauce separate or turn grainy?

​Separation happens when dairy gets overheated or if pre-shredded packaged cheese is used. Always use freshly grated Parmesan cheese from a block and keep your burner on low heat when melting the cheese.

​Can I prep this keto casserole ahead of time?

​Absolutely! You can assemble the entire casserole in your baking dish earlier in the day, cover it, and store it in the fridge until you are ready to bake. Add an extra 5 minutes to the baking time if cooking from cold.

​Is this recipe completely gluten-free?

​Yes, this recipe is naturally 100% gluten-free and grain-free because it omits all wheat flour, starches, and pasta noodles entirely.

​Pro Tips for Best Recipe

​Grate Your Own Cheese: Never use pre-shredded bagged mozzarella or parmesan. Bagged cheese contains anti-caking cellulose powders that prevent smooth melting and cause a gritty sauce texture.

​Do Not Over-Boil Broccoli: Blanch the broccoli for only 2 minutes. It will finish cooking inside the hot oven; over-boiling beforehand will turn the florets into mush.

​Sauté Garlic Low and Slow: Garlic burns quickly in hot butter and turns bitter. Keep your skillet heat on medium-low when sautéing the minced garlic.

​Let It Rest Before Serving: Allow the baked casserole to rest on the counter for 10 minutes before scooping. This gives the cheese and sauce time to set up so your servings hold their shape.

Try These Recipes Also

Low Carb Chicken Alfredo Pizza

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