### Instructions
1. **Prep the Meat and Aromatics:** In a large skillet or Dutch oven, brown the ground beef (or Italian sausage) over medium-high heat, breaking it up with a spoon. Drain off any excess grease. Add the chopped onion and cook until softened, about 5-7 minutes. Stir in the minced garlic and cook for another minute until fragrant.
2. **Build the Sauce:** Pour in the marinara or pizza sauce. Stir in the dried oregano, dried basil, and red pepper flakes (if using). Bring to a simmer, then reduce heat to low and let it gently simmer for 10 minutes, allowing the flavors to meld.
3. **Combine and Layer:** Preheat your oven to 375°F (190°C). In a large bowl, combine the cooked and drained egg noodles with half of the meat sauce mixture. Stir well to coat the noodles.
4. **Assemble the Casserole:** Spread half of the noodle mixture into a 9×13 inch baking dish. Top with half of the shredded mozzarella cheese and half of the pepperoni slices.
5. **Second Layer:** Spoon the remaining half of the meat sauce mixture over the pepperoni layer. Then spread the remaining noodle mixture on top.
6. **Final Touches:** Sprinkle the remaining mozzarella cheese over the top of the casserole. Arrange the remaining pepperoni slices evenly over the cheese.
7. **Bake:** Bake for 20-25 minutes, or until the cheese is melted and bubbly and the casserole is heated through. If desired, you can broil for the last minute or two to get a golden-brown crust on the cheese, watching carefully to prevent burning.
8. **Serve:** Let the casserole rest for 5-10 minutes before serving. This allows it to set up slightly and makes for easier serving. Serve hot and enjoy!
### Short Tips
* **Make it Ahead:** You can assemble this casserole a day in advance and store it in the refrigerator. Just add 10-15 minutes to the baking time to ensure it heats through evenly.
* **Spice it Up:** For more heat, add extra red pepper flakes or a pinch of cayenne pepper to the sauce.
* **Vary the Veggies:** Feel free to add diced bell peppers, mushrooms, or black olives to the meat sauce for extra flavor and nutrients.
* **Cheese Please:** Don’t be shy with the cheese! You can add a sprinkle of Parmesan or a blend of Italian cheeses for extra richness.
* **Kid-Friendly:** If you have picky eaters, you can easily omit the red pepper flakes and serve with a side of their favorite dipping sauce.
