Preheat the oven to 350 degrees. Spray a 9×13 baking dish with non-stick cooking spray and set it aside.
Cook the pasta in a large pot of water to al dente. Drain well.
In a large stock pot on medium-high heat, brown the ground beef, bell pepper, and diced onion. Drain excess grease.
Add the Manwich sauce, cooked bowtie noodles, and half the shredded cheese. Stir the ingredients until well combined.
Spoon the pasta and ground beef mixture into the prepared casserole dish. Cover with aluminum foil and place in the preheated oven. Bake for 20 minutes.
After 20 minutes, remove the foil and sprinkle with the remaining cheese. Place under the broiler for 1-2 minutes until the cheese is melted and golden brown.