• Preheat the oven to 350°F.
• Grease or spray a 9x13-inch casserole dish with nonstick cooking spray.
• Cook the rotini pasta according to the package directions until it reaches a firm al dente texture. The pasta should remain slightly firm, as it will continue cooking in the oven.
• Drain the pasta and rinse it under cold water to stop the cooking process. Set aside.
• In a large skillet over medium heat, cook the ground beef and mild Italian sausage until fully browned, breaking the meat into small crumbles as it cooks.
• Drain the excess grease from the skillet, reserving approximately 1 tablespoon of grease in the pan.
• Transfer the cooked ground beef and sausage mixture to a bowl and set aside.
• Add the diced onion and chopped mushrooms to the skillet with the reserved grease.
• Cook until the onion and mushrooms are softened.
• Add the minced garlic and sauté for 2 to 3 minutes, stirring frequently to prevent burning.
• Stir in the Italian seasoning, diced tomatoes, tomato sauce, and white sugar.
• Allow the sauce to simmer briefly until heated through and combined.
• Return the cooked ground beef and Italian sausage mixture to the skillet.
• Stir until the meat is evenly coated with the tomato sauce mixture.
• Remove the skillet from the heat.
• Spread a small amount of the meat sauce over the bottom of the prepared casserole dish.
• Add the cooked rotini pasta over the sauce and spread it evenly.
• Sprinkle the shredded Italian cheese blend evenly over the pasta.
• Pour the remaining meat sauce over the cheese and pasta layer, spreading it evenly across the dish.
• Cover the casserole dish with foil.
• Bake for 45 minutes, or until the casserole is hot and bubbling.
• Remove the foil and sprinkle the shredded sharp Cheddar cheese evenly over the top.
• Return the casserole to the oven and bake until the Cheddar cheese is fully melted and bubbling.
• Remove the casserole from the oven and allow it to rest for 5 to 10 minutes before serving.
• Spoon portions onto plates and serve warm.

Slow Cooker Instructions

• Grease or spray the inside of the slow cooker with nonstick cooking spray.
• Cook the rotini pasta according to the package directions until firm al dente.
• Drain the pasta and rinse it under cold water to stop the cooking process. Set aside.
• In a large skillet over medium heat, cook the ground beef and mild Italian sausage until browned and fully cooked.
• Drain the excess grease, reserving approximately 1 tablespoon in the skillet.
• Transfer the cooked meat mixture to a bowl and set aside.
• Add the diced onion and chopped mushrooms to the skillet.
• Cook until softened.
• Add the minced garlic and sauté for 2 to 3 minutes.
• Stir in the Italian seasoning, diced tomatoes, tomato sauce, and white sugar.
• Simmer briefly, then return the cooked meat mixture to the skillet.
• Stir until fully combined, then remove from the heat.
• Spread a small amount of meat sauce over the bottom of the prepared slow cooker.
• Add the cooked pasta over the sauce.
• Sprinkle the Italian cheese blend evenly over the pasta.
• Pour the remaining meat sauce over the top.
• Cover and cook on low for 1 1/2 to 2 hours, or until the casserole is heated through.
• Sprinkle the shredded sharp Cheddar cheese over the top.
• Cover again and allow the cheese to melt.
• Spoon portions onto plates and serve warm.