In an oven-safe pan saute the onions and garlic then add the diced sausage until sealed.
In a bowl mix together ricotta, heavy cream, eggs, salsa and cayenne pepper then pour the mixture over the sausage, garlic and onions.
Pre-heat your oven to 350 F then bake for 20 minutes or until the mixture begins to firm.
Top with grated cheese then place until the grill until golden. Let it cool before slicing and serve with sour cream.