Bring a large pot of salted water to a boil. Cook the gluten-free ziti until just al dente, about 7–8 minutes. Drain and set aside.

While the pasta cooks, heat a large skillet over medium heat. Add the ground beef and cook until browned, breaking it up as it cooks.

Stir in the chopped onion, red bell pepper, Italian seasoning, salt, and pepper. Cook for 4–5 minutes, until the vegetables soften.

Add the pasta sauce to the beef mixture and let it simmer gently until the pasta is ready.

Spoon a small amount of sauce into the bottom of a baking dish to prevent sticking.

Add a layer of cooked pasta, followed by a layer of meat sauce. Dollop ricotta over the sauce and sprinkle with mozzarella.

Repeat the layers until all ingredients are used, finishing with mozzarella on top.

Cover tightly with foil and bake for 30 minutes, or until hot and bubbly throughout.

Let rest for a few minutes before serving.