Preheat the Oven : Preheat your oven to 375°F (190°C).

Cook the Beef Mixture : In a large skillet over medium heat, cook the ground beef until browned. Add the diced onion and minced garlic, cooking until the onion is softened. Stir in the Italian seasoning, salt, and pepper.

Prepare the Sauce : Lower the heat and add the cream cheese to the skillet. Stir until melted and fully incorporated. Gradually mix in the heavy whipping cream and beef broth. Simmer for 3–4 minutes until the mixture thickens slightly.

Add the Cheese : Stir in 1 cup of mozzarella cheese and 1 cup of cheddar cheese, mixing until melted and creamy.

Assemble the Casserole : In a greased 9x13-inch casserole dish, layer the thawed broccoli at the bottom. Pour the beef and cheese mixture over the broccoli, spreading evenly. Sprinkle the remaining mozzarella and cheddar cheese on top.

Bake the Casserole : Bake in the preheated oven for 20–25 minutes or until the cheese on top is bubbly and golden.

Serve and Enjoy : Let the casserole cool slightly before serving. Enjoy this hearty, keto-friendly dish on its own or with a fresh side salad.