Combine first 7 ingredients in a gallon resealable freezer bag; freeze. Thaw completely. Place in a greased slow cooker. Cover, cook on low for 7-8 hours. Combine sour cream and corn starch, mix well. Stir into slow cooker until well blended; cook an additional 15-20 minutes until sauce thickens. Pour over pasta. Makes about 6 servings.
Sides: vegetable of choice