Crush the yeast in 120 ml water - warm, but not hot, with sugar and let stand for 5 minutes, until mixture begins to bubble. In a large bowl mix the flour with your hands, yeast 5 tbsp olive oil and salt. If necessary add more water - 150 -200 ml Spread the dough in the form of tart, pre-greased with olive oil 2-3 tbsp. Cover with towel and let the dough rise for 1 hour. Meanwhile, wash the tomatoes, cut them in half and sprinkle with olive oil, salt and oregano. Stir and set aside. Preheat oven to 200 C. Arrange tomatoes on the risen disc of dough by squeezing them tightly together. Scatter the olives and place in the oven to bake for 30-40 minutes. Serve the tart warm or cold * Optional, before removing the tart from the oven, you can sprinkle the top with grated cheese. * tartan happens with finished dough