Add cauliflower to food processor and process to small pieces. Add to saute pan with 3 cloves garlic, olive oil and 1 tbsp of italian seasoning and salt and pepper. Saute until cooked through. Add to 9x13 pan.
In a separate sauce pan heat tomato sauce, 3 cloves garlic, 1 tbsp italian seasoning, and salt and pepper. Simmer 30 minutes.
Brown italian sausage and mix with tomato sauce.
On top of cauliflower pour half of sauce/sausage mixture, 1/2 of cheese, 1/2 peppers, mushrooms and olives. Repeat with a second layer.
Bake at 350 degrees for 20 minutes.