Preheat the oven at 180° C.

Cook the pasta following the instructions on the package.

Pour olive oil into a pan to stir-fry the garlic, parsley, onion, bell peppers, and mushrooms for 5 minutes.

Add the tomato paste and cook for another 5 minutes.

Stir-fry the beef sauce and add it to the sauce and cook.

Grease the bottom of a casserole and place a layer of lasagna sheets, then a layer of the beef sauce, and then a layer of mozzarella. Repeat the layers until you reach the top of the casserole and cover it with mozzarella.

Bake for 45 minutes or until the cheese is browned. Let it cool for 10 minutes and serve.