Preheat your oven to 350°F (175°C).

Heat olive oil in a skillet and cook diced onions until softened and translucent.

Add ground beef, breaking it up as it browns. Drain excess fat and stir in puréed tomatoes and Italian seasoning. Simmer for 15 minutes.

Cook pasta according to package instructions and drain.

In a 9x13-inch casserole dish, layer the ingredients: start with a thin layer of sauce, followed by half the pasta, half the remaining sauce, and half the cheese. Repeat the layers.

Bake in the oven for 30 minutes, or until bubbly and golden on top.