Baked Shells with Pesto, Mozzarella and Meat Sauce

INGREDIENTS

1 tbsp

olive oil

onion (chopped)

fresh basil leaves or 1 tsp dried basil

lbs ground beef (extra-lean)

cups/800 gr/2 cans chopped tomatoes

1 1/2 tsp

salt

1/2

cup/ 125 ml store-bought pesto

lbs pasta shells

1 1/2

cups/150 gr mozzarella (grated)

1/4 cup

freshly grated Parmesan