Cook shells according to package ... together mayonnaise, marinara sauce, milk, salt, and oregano in large bowl. Add macaroni, pepperoni, and celery; toss ... at least 2 hours.
Heat oven to 350 degrees. ... square pan. Prepare macaroni according to package directions; drain. ... Stir in spaghetti sauce and mushrooms. Simmer 15 minutes. ... Refrigerate leftovers. 6 servings.
Ingredients: 9 (beef .. cheese .. salt .. sauce ...)