Pick tomatoes with a skewer, halve them and place on a bed of rock salt, skin side down. Drizzle with half the olive oil and sprinkle with black pepper. Bake in a low oven (100°C) for about 1 hour.

To make the onion jam, melt the butter in a heavy-bottomed saucepan. Add onions and cook on very low heat for 10 minutes. Add the honey and wine and cook over very low heat for about another 45 minutes. Add the vinegar and season to taste.

Chop basil and add it to the remaining olive oil, leaving it to infuse.

Preheat oven to 180°C . With a sharp knife score the fat side of the lamb rumps in a criss-cross pattern. Salt the meat and in a hot pan seal the meat: fat side down first, then the other side. Transfer to oven and cook for 8-10 minutes. Let meat rest for 5 minutes then slice it against the grain, cutting each rump into 4 pieces.

To serve, place 2 tomato halves on each plate, arrange the lamb slices over them and garnish with a tablespoon of red onion jam. Drizzle the basil-infused oil over the top.

Chef's tip: red onion jam works with fish as well as meat: try poaching fish in equal quantities of wine and stock, then serve with steamed asparagus and spoonful of onion jam finished with a drizzle of olive oil.