Add the yeast to the lukewarm water with ½ teaspoon sugar for 2 minutes. Combine the flour and salt in a large mixing bowl. Make a well in the centre and add the water/yeast mixture whilst mixing the dough together with your hands or a metal spoon until you have obtained a dough. If it's too sticky you can gradually add a little more flour.
Dust a clean work surface with a little flour and knead the dough for around 10 minutes until it's silky smooth and soft. If you lightly press your finger on the ball of dough it should spring back up easily.
Add 1 tablespoon of olive oil to a large clean bowl and rub all over until the bowl is coated. Shape the dough into a ball and place in the bowl, rub the top of the dough with a tiny amount of olive oil. Cover with cling film and leave in a warm place for at least 3 hours until doubled in size.
To make the onions, add the oil to a pan and add the onions. Cook until translucent and soft. Add the sugar and stir then add the vinegar and water. Let the onions get jammy then turn off the heat. Add a little salt.
When you are ready to make the pizzas pre-heat the oven to 225°C.
Divide the dough in half roughly with your hands. Lightly dust a work surface with flour and begin to roll out your first half of dough. The pizzas can be made round or rectangle depending on your baking trays. Roll out the dough as thin as possible without tearing around 30cm in diameter. Lightly dust the baking/pizza trays with semolina then place the dough on the tray, repeat with the second half of dough on a separate tray.
To top the pizzas spread 2-3 tablespoon of passata on each pizza and then sprinkle on the oregano and a little salt and pepper.
Top with even amounts of stuffing, turkey, brie, onions and mozzarella. Bake in the oven for around 10 minutes until the cheese is bubbling and crust is golden.