In large Dutch oven or other heavy-bottomed pot over medium heat, heat oil. Add fennel and onion and cook, stirring often, 7 to 9 minutes until soft. Add sausage; cook 7 to 9 minutes, crumbling as you cook, until sausage is cooked through and browned. Add garlic, crushed fennel seeds, red pepper flakes, 2 teaspoons salt and 1 teaspoon black pepper. Cook for 1 minute, then pour in white wine. Bring to boil. Add heavy cream, half-and-half and tomato paste. Return to boil, then reduce heat and simmer 20 minutes, stirring occasionally, until sauce thickens.

Meanwhile, bring large pot of water to boil. Add 2 tablespoons salt to boiling water, then add rigatoni pasta. Cook according to package directions. Drain and add to sauce; stir to coat pasta.

Off heat, stir in 1/4 cup parsley and 1/2 cup Parmesan cheese. Serve topped with remaining parsley and Parmesan cheese.