- Preheat oven to 375 degrees. Grease a 9x13 casserole dish.
- Cut cauliflower into florets. Bring a large pot of water to boil and place florets in it. Cook for about 3 minutes. Remove from heat and drain then set aside.
- In a bowl combine the oregano, tomato paste, and crushed tomatoes. Stir the ingredients together and set aside.
- Heat olive oil over medium heat. Add onion and cook until softened. Add garlic and red pepper flakes and cook another minute. Add ground beef along with salt and pepper and cook until browned.
- Add in the tomato mixture and stir until incorporated. Lower heat and simmer for 15 minutes.
- In a bowl stir the cheeses together.
- Add the florets to the meat sauce and gently stir.
- Pour half the cauliflower mix into the pan and spread out evenly. Put half the cheese on top and then add the rest of the cauliflower. Top with the remaining cheese.
- Place in oven and bake for 25 minutes. Let stand for 10 minutes before cutting.