Heat oven to 375°F. Lightly grease a 9x13-inch baking dish.
Boil noodles in salted water until al dente. Drain well.
Warm olive oil in a large skillet over medium-high heat.
Cook onion and bell pepper until soft, about 4 minutes. Stir in garlic for 30 seconds.
Add ground beef. Cook, crumbling, until browned; drain excess fat.
Stir in tomato sauce, ketchup, tomato paste, and beef broth.
Add Worcestershire, mustard, brown sugar, chili powder, paprika, red pepper flakes, salt, and pepper.
Simmer the mixture until thickened slightly, 5 to 7 minutes.
Toss sauce with drained noodles. Fold in half the cheddar.
Spread into the dish. Sprinkle remaining cheese over the top.
Bake until bubbling and melted, 12 to 15 minutes. Rest 5 minutes.
Finish with parsley and serve warm.
Notes
Variation: Swap the noodles for tater tots or biscuit pieces, and bake until the topping is crisp and golden. Want it lighter? Use ground turkey and a reduced-sodium broth, then add a splash of vinegar to brighten the sauce.Storage: Refrigerate leftovers in an airtight container for up to 4 days, or freeze up to 2 months. Reheat covered at 350°F until hot.This recipe is an original creation inspired by classic Easy Sloppy Joe Casserole Recipe flavors. All ingredient ratios and instructions are independently developed.