Put oil and the chopped half onion in a skillet.

When the onion begins to soften, add the ground meat and season with salt and pepper.

Once cooked, add the tomato passata, stir it, cook for a couple of minutes, then remove from the heat.

Begin assembling everything.

Place sauce on the bottom, then lasagna sheets, a layer of meat, and grated mozzarella; cook over very low heat.

Repeat layers of lasagna sheets, meat, and grated mozzarella until the skillet is filled.

Cover the surface with more grated mozzarella.

Cook until the mozzarella has melted and becomes stretchy.