Prepare everything - Preheat your oven to 350°F. Spray a 9x13 inch baking dish generously with cooking spray. Bring a large pot of salted water to a rolling boil.

Cook pasta just right - Add spaghetti to boiling water and cook 8-11 minutes until al dente (follow package directions but test early). Drain thoroughly and set aside.

Brown the meat mixture - In a large skillet over medium heat, cook ground beef, diced onion, and bell pepper together for 8-10 minutes. Stir frequently to break up meat and cook until beef is completely browned and vegetables are tender.

Add garlic - Stir in minced garlic and cook 1 additional minute until very fragrant.

Drain well - Remove all excess grease from the meat mixture using a colander or paper towels. Transfer to a large mixing bowl.

Make the creamy sauce - Add diced tomatoes with their juice, cream of mushroom soup, chicken broth, frozen corn, frozen peas, chili powder, salt, and pepper to the beef mixture. Stir everything together until well combined.

Combine with pasta - Add the cooked spaghetti to the beef and vegetable mixture. Using tongs or a large spoon, gently toss everything together until pasta is evenly coated.

Assemble and bake - Transfer mixture to your prepared baking dish and spread evenly. Sprinkle grated cheddar cheese over the entire top. Bake 15-20 minutes until cheese is completely melted and casserole is hot and bubbly.

Rest and serve - Allow to cool for 5 minutes before serving. Serve hot and enjoy!