Dissolve the yeast in warm water. Add flour, and a pinch of salt and knead the dough until it is smooth and elastic.
Roll out the dough with a rolling pin, place it on a greased baking sheet and leave it to rise for about 40 minutes, covered with a clean tea towel.
In the meantime, drain the can of peeled tomatoes in a colander, pressing down gently to remove any excess juice. Then, roughly chop them. Roll out the dough evenly and place it on a greased baking sheet or pizza pan. Spread the chopped tomato evenly over the dough, leaving a border of about 2 cm. Sprinkle over 2–3 thinly sliced garlic cloves and 2–3 teaspoons of dried oregano. Drizzle generously with three tablespoons or so of olive oil. Season with salt and freshly ground black pepper.
Bake in the centre of a preheated oven at 230°–240°C (450°– 475°F/Gas 8–9) for 8–10 minutes until crisp.