Cook pasta al dente according to package directions. Add to a 9x13 inch baking dish.
Heat butter in a medium sauce pan and add sausage. Cook over medium heat until browned. Remove from the saucepan and place in baking dish.
Add cream cheese to the pan and stir until melted. Add Alfredo sauce and cream, heat until it begins to bubble. Turn the heat off and stir in the cheddar and parmesan.
Pour the sauce over the pasta and mix well.
Combine topping ingredients and sprinkle over the top. Bake 18-20 minutes or until browned and bubbly.
Notes
Bring cream cheese to room temperature so it will mix easily with the other ingredients.
Prep everything in advance, cover, and chill until ready to top and bake.
Refrigerate leftovers covered for up to 5 days.
Reheat portions in the microwave, or covered with foil in the oven until just heated through. Add a bit of milk if needed.