Preheat oven to 350 degrees and prepare a 9 x 13-inch baking pan with cooking spray.
Cook the pasta in a large pot according to packaged directions until al dente. Drain and set aside.
In a large skillet on medium-high heat Add the onions, ground beef, bacon, tomatoes cook until beef is cooked all the way. drain to get rid of grease.
In a small bowl mix ketchup, mustard and relish.
In the large pot with the pasta add the meat mixture and ketchup/mustard/relish mixture and 2 cups cheese and stir till mixed well
Pour into a baking pan and bake for 15 minutes (make sure cheese is melted)