Preheat oven to 375°F

Cook penne according to package directions

Heat oil in skillet on medium heat

Brown sausage in skillet for 5 minutes

Combine milk and soup in the mixing bowl

Add 1/2 cup of french onions, 1/4 cup mozzarella, 1/4 cup cheddar cheese, and sausage to the milk and soup

Drain pasta

Add pasta to the mixture and stir thoroughly

Spray casserole dish with cooking spray

Pour mixture into casserole dish

Cover casserole dish with foil

Bake for 30 minutes in preheated oven

Remove foil

Sprinkle with onions and remaining cheese

Bake, uncovered, for 5 minutes until cheese is melted

Serve