In a blender or food processor, place first 6 ingredients (tomato sauce through red pepper); process until smooth. With the blender or food processor running, slowly add the avocado oil; blend well then set aside.
Heat a large skillet over medium heat. Add the sausage; cook, breaking it up with a spoon, for 2 to 3 minutes. Add onion; cook until soft and sausage is cooked through. Reduce skillet heat to low. Add the sauce from the blender or food processor; bring mixture to a simmer, cook for 2 to 4 minutes then remove from heat. Spoon a thin layer of meat mixture on the bottom of a large crock cooker.
Next, layer half of the cauliflower and zucchini, then one-third of the meat mixture; repeat this process, finishing with the remaining meat mixture. Cover and cook on LOW for 4 hours. Serve hot.