Make the dough: In a large bowl, dissolve the yeast in the water. Add the sugar and gradually mix in the flour, starting to knead. Add the salt and olive oil, and knead the dough for at least 10 minutes, until smooth and elastic.

First rise: Cover the dough with a kitchen towel and let it rise for about 3 hours, or until doubled in size.

Prepare the topping: In a bowl, mix the tomato puree with salt, pepper, a drizzle of olive oil, and plenty of oregano.

Shape the dough: Roll out the dough on a lightly floured surface to about 1/6 inch (4 mm) thick. Use a 2 3/4–3 1/2 inch (7–9 cm) round cutter to cut out circles. Place them on a baking sheet lined with parchment paper and let them rest for 10 minutes.

Top the pizzas: Spoon some tomato sauce onto each mini pizza. Add diced mozzarella, a drizzle of olive oil, and a pinch of oregano.

Bake: Bake in a preheated conventional oven at 400°F (200°C): 10 minutes on the lower rack, then 5 minutes on the upper rack to brown the tops.