Heat the oven to 180°F C

In a large heavy bottomed saucepan, heat the olive oil

Fry the onion until soft

Add the garlic

Add the beef mince an cook for a few minutes until brown

Add the tomatoes, herbs and tomato puree

Cook for 20 minutes

Meanwhile, scoop out the middles of the marrow rings

Place them in a large baking dish

Spoon a portion of the mince sauce into each

Distribute the remainder over the top of the marrow rings

Cover with foil and bake in the oven for about 30 minutes

Remove the foil, sprinkle with cheese and return to the oven uncovered for 10 minutes