Place the beef tomato wedges into an oven proof dish. Heat the olive oil and saute the onion until soft and then lift out the onion and arrange it on and around the beef tomato in the oven proof dish. Keep the oil to use later. Scatter the olives and sun dried tomatoes and half the parsley over the tomatoes and onions.
Drizzle the oil used to saute the onion over the mixture. Bake the mixture at 200C for 15 - 20mins. Watch carefully as the mixture can burn easily. Arrange the spinach onto a serving dish followed by the hot tomato mixture over the spinach. Drizzle the juices over the top and finish off by sprinkling the other half of the parsley and Parmesan over the top.