Pissaladière, Provençal Onion Tart

	Sift the flour with salt into a bowl, add the yeast. Gradually pour in the water and oil. Knead the dough for 5 minutes. Cover with plastic wrap and let it rise for 1 hour.
	Thoroughly wash the leek, peel the onion. Cut the white part of the leek and the onion into thin half-rings. Heat oil in a deep pan, add the onion and sauté for 10 minutes, stirring. Then add the leek and sauté for another 3 minutes.
	Pour boiling water over the tomatoes. Peel off the skin. Cut the flesh into small pieces. Rinse the thyme well, dry, and chop.
	Add the tomatoes and thyme to the onions, season with salt and pepper to taste, and mix. Cover and simmer the vegetables for 45 minutes. Remove the lid for the last 10 minutes. Remove from heat and cool to room temperature.
	Cut off the heads and tails of the fish, remove the entrails. Divide each fish into two fillets, discarding the backbone and large rib bones.
	Preheat the oven to 200 °C. Grease a baking sheet with oil. Roll out the dough into a thin pancake, place it on the baking sheet, and shape the edges with your hands. Evenly spread the onion filling on the dough. Lay the fish strips on top in a lattice pattern, placing an olive in the center of each diamond. Bake for 30 minutes.