Combine first 3 ingredients in a large bowl; stir until blended.
Beat the cream cheese and sour cream with a mixer at low speed until smooth (about 2 minutes).
Spread half of pasta mixture in bottom of a 3-quart casserole coated with cooking spray; spread the cream cheese mixture evenly over pasta mixture. Top with remaining pasta mixture; sprinkle the mixture with the mozzarella cheese.
Cover and refrigerate 24 hours.
Preheat oven to 350°.
Bake, covered, at 350° for 50 minutes. Uncover and bake an additional 10 minutes or until the cheese is browned.