Preheat your oven to 375°F (190°C) and lightly grease a baking dish

Heat olive oil in a large skillet over medium heat

Add diced onions and cook for 2–3 minutes until softened

Stir in minced garlic and cook for 30 seconds until fragrant

Add ground beef and cook until browned, breaking it apart evenly

Season with Italian seasoning, paprika, salt, and pepper while cooking

Drain excess grease to avoid a heavy casserole

Add cauliflower rice to the skillet and stir well

Cook for 3–5 minutes until slightly softened and moisture reduces

Stir in chopped spinach and cook until wilted

Add butter and sour cream, mixing until creamy and combined

Sprinkle in half of the cheddar and mozzarella cheese and mix thoroughly

Transfer the mixture evenly into the prepared baking dish

Spread it out evenly using a spatula

Top with remaining cheddar, mozzarella, and parmesan cheese

Place in the oven and bake for 20–25 minutes until cheese is melted and bubbly

Turn on broil for 2–3 minutes for a golden, slightly crispy top

Remove from oven and let rest for 5–10 minutes before serving

Garnish with fresh herbs if desired

Slice and serve warm