In a bowl, add the water and then the yeast and leave it aside. Place the flour and salt in the bowl of a mixer. Place the hook and stir the ingredients at low speed. Slowly add the water with the yeast. Mix the dough until it sticks to the hook. If it’s too sticky add a tablespoon of flour. Remove the dough from the bowl and knead with your fists on a clear surface. Then cut the dough into four pieces. Form in balls, sprinkle a baking pan with a little flour, place the dough balls, cover with a towel and allow to rest for 2 hours.
In a saucepan, add the olive oil and fry the onion. When softened add remaining ingredients. Stir and when the sauce starts to boil, lower the heat and simmer for 20 minutes. Remove the basil leaves and let the sauce cool down slightly. Using a rolling pin, roll out the dough in round shapes. Spread some sauce (avoiding the edges). Add mozzarella, fresh vegetables or cold cuts, and bake in the oven for about 20 minutes until the cheese melts and the edges turn golden brown.