1.Fill A Large Pot With Lightly Salted Water And Bring To A Boil. Stir In The Rotini, And Return To A Boil. Cook Uncovered, Stirring Occasionally, Until The Pasta Has Cooked Through But Is Still Slightly Firm, About 8 Minutes. Drain Well. 2.Heat A Large Skillet Over Medium-High Heat And Stir In The Sausage. Cook And Stir Until The Sausage Is Crumbly, Evenly Browned, And No Longer Pink. Drain And Discard Any Excess Grease. Stir In The Spinach And Tomatoes, And Cook Until The Spinach Is Wilted, About 3 Minutes. Mix In The Cooked Rotini Pasta, Mozzarella Cheese, And Parmesan Cheese. Toss Until Cheese Is Melted.