Step 1

Preheat oven to 350° F. Lightly grease a 9x13-inch baking dish or other large rectangular baking dish.

Step 2

Bring a large pot of salted water to a boil. Add the pasta and cook according to package directions for al dente. Be careful to not overcook the pasta. Reserve ½ cup of the pasta cooking water and then drain the pasta. Return the drained pasta to the pot.

Step 3

Meanwhile, heat the olive oil in a large skillet over medium high heat. Add the onion and bell pepper to the pan and cook, stirring often, until the vegetables soften, 3 to 4 minutes. Add the garlic and cook, stirring, for 30 seconds. Add the ground beef to the pan. Crumble the beef and cook until it is browned.

Step 4

Pour the marinara sauce and reserved ½ cup of pasta cooking water into the skillet. Stir in the salt and pepper. Bring to a simmer and reduce the heat to low. Simmer for about 10 minutes.

Step 5

Pour the meat and sauce mixture from the skillet into the pot with the pasta. Stir. Stir in the shredded cheddar cheese. Transfer the pasta mixture to the prepared casserole dish. Top with the mozzarella cheese.

Step 6

Bake for 20-25 minutes, until the casserole is hot and the cheese is lightly browned on top. Let stand for 5 minutes and then serve.