Preheat your oven to 350°F (175°C).

In a large skillet over medium-high heat, add the ground beef and cook until it’s thoroughly browned, about 5-7 minutes.

Once the beef is browned, stir in the chopped onion, green and red bell peppers, and minced garlic. Sauté for 5-7 minutes until they soften and become fragrant.

Add in the petite diced tomatoes, ketchup, yellow mustard, and brown sugar to the skillet. Season with salt and black pepper, stirring everything together well. Reduce the heat and let it simmer uncovered for about 10 minutes.

While the meat mixture simmers, bring a large pot of water to a boil. Add the penne pasta and frozen corn, cooking them according to package directions until tender, about 8-10 minutes. Drain and set aside.

In a large bowl, combine the drained corn and cooked pasta with the skillet mixture. Gently fold in the shredded Colby-Jack cheese.

Spray a 9x13-inch baking dish with non-stick cooking spray, then spread the Sloppy Joe mixture evenly into the dish.

Place the baking dish in your preheated oven and bake for 20 minutes, or until the casserole is heated through and the cheese is bubbly and slightly golden.