Cook the ziti pasta according to the package instructions until it’s al dente. Drain the pasta and set it aside.

In a large skillet over medium-high heat, add the olive oil. Once hot, toss in the diced onions and bell pepper. Cook for about 2-3 minutes until they soften.

Add the Italian sausage and ground beef to the skillet. Cook until their pink color disappears, making sure to crumble the meat as it cooks. Drain any excess grease.

To the cooked meat, add the marinara sauce, drained diced tomatoes, and seasonings (Italian seasoning, garlic powder, onion powder, salt, and pepper). Stir to combine, then let the sauce simmer for a few minutes.

Gently fold the cooked ziti pasta into the skillet, mixing until the pasta is well coated in the sauce.

In a separate bowl, combine the ricotta cheese and egg. Mix until smooth.

In a 9×13-inch casserole dish, create layers. Start with a layer of the meat sauce and pasta, spread a thin layer of the ricotta mixture over the top, and repeat these layers two more times. Finish with a final layer of pasta.

Sprinkle the shredded mozzarella and cheddar cheese over the top layer of pasta. Cover the dish tightly with foil.

Place the casserole in a preheated oven at 350°F (175°C) and bake for 20-30 minutes.

After baking, remove the foil and switch the oven to broil on high. Broil for an additional 2-3 minutes until the cheese is bubbly and golden brown.