Cut the onion in half and peel away the skin from the tip down to the root base. Trim each end and then slice each half so it keeps it’s shape. Spread out on a lightly oiled baking sheet (I line it with parchment then oil that). Drizzle with a little olive oil, sea salt and pepper and roast at 200c/180cfan/gas6 for 15 minutes.
Meanwhile prepare the tomatoes. Wash them and then slice the large ones from the top where the stork was, to the base, then slice each half into quarters, set aside. Cut the other tomatoes around the circumference middle. Peel the garlic and thinly slice the again into sticks and perhaps in half again if they are long. Pop one piece into each tomato.
Remove the onions from the oven and reduce the heat to 180c/160cfan/gas 4. Place the tomatoes on top of the onions, put the smaller ones in the middle. Drizzle with olive oil then mix the sea salt, pepper, oregano and sugar together- sprinkle over the tops of the tomatoes making sure they all get a little dusting.
Finish with half of the herbs over the top and bake for about 40 minutes until slightly shrunk and a little toasted at the edges. If they are not quite there leave them a little longer.
Remove from the oven and add the olives immediately and finish with the remaining fresh herbs.
