Preheat Oven to 400 F, and grease or oil a 2.5 quart casserole dish.
In a food processor or blender, grind cauliflower florets into a rice texture.Set aside.
In a large skillet pan over medium high combine and brown: 1 lb ground beef, ½ teaspoon garlic powder, ½ teaspoon paprika, ½ teaspoon sea salt, ¼ teaspoon celery seed, and ¼ teaspoon black pepper. Stir and cook until browned (do not drain beef).
Add 8 ounces tomato sauce and 3 cups cauliflower rice to the ground beef skillet. Stir and continue cooking over medium to medium high heat for 6 minutes. Remove from heat.
Carefully spoon or dump all ingredients from the skillet into the casserole dish. Spread around casserole dish evenly.
Sprinkle the top of the casserole with bacon crumbles and optional cheese. Place sliced tomatoes on top, and bake for 20 mins. Remove from oven and serve.