4beef sirloin steaks (about 200gm each), at room temperature2 tbsporegano, plus extra to serve2garlic cloves, coarsely choppedFinelygrated rind and juice of 1 lemon50 mlextra-virgin olive oil, plus extra to serve1 tbspbalsamic vinegar, plus extra to serve4vine-ripened or small oxheart tomatoes, thickly sliced200 gmmixed cherry tomatoes, halved100 gmfirm ricotta, coarsely crumbledQuick onion pickle2Spanish onions, sliced into thick rounds1½ tbspolive oil, plus extra for brushing1garlic clove, finely chopped1 tbspbalsamic vinegar
Place steaks in a non-reactive oven dish and set aside. Pound oregano, garlic, lemon rind and 1 tsp sea salt in a mortar and pestle to a coarse paste. Add lemon juice, oil and vinegar, season to taste, then pour mixture over steaks, turn steaks to coat and stand to marinate (20 minutes).
Meanwhile, for quick onion pickle, preheat barbecue to medium-high heat. Lightly brush onion and barbecue with oil, then grill onion, turning occasionally, until tender and browned (3-4 minutes). Transfer to a bowl, add remaining ingredients and set aside.
Drain steaks from marinade and grill, turning once, until cooked to your liking (2-3 minutes each side for medium-rare) then set aside on serving plates to rest (5 minutes).
Place tomato on plates, scatter with ricotta and extra oregano and drizzle with extra oil and vinegar to taste. Serve with steaks topped with quick onion pickle.