Over medium heat, heat olive oil in a dutch oven.  Add the chopped fennel and onion and saute, stirring occasionally for 7 minutes, until tender.

Add the sausage to the dutch oven and break up with a wooden spoon.  Cook for about 8 minutes, until sausage is browned, breaking up the meat and stirring occasionally.  Add the garlic, crushed fennel seeds, red pepper flakes, salt and black pepper, and let cook for 1 minutes.

Pour in the white wine, and bring to a boil.  Then add in the heavy cream, half and half, and tomato paste.  Bring mixture back to a boil.  Lower heat and let mixture simmer for 20 minutes, until the sauce has thickened.

While sausage and sauce is simmering, boil water, add 2 tablespoons salt, and cook rigatoni according to package instructions (usually 10 minutes in boiling water).

Drain noodles, and add to the sauce, stir to coat the pasta.  Remove dutch oven from heat and stir in parsley and parmesan cheese.  Serve immediately.  Oh my goodness, so good!!