Preheat oven to 220C Fan Forced.
Place flour, yoghurt, baking powder, 1 tablespoon of olive oil and 1 tsp salt in a food processor. Pulse until it forms a dough. Place dough on a floured surface and form a ball. Roll out with a rolling pin to form a 30cm circle.
Combine garlic and oil in a small bowl, then season with salt and pepper. Brush some of the oil over the pizza tray. Cover with dough and brush with more oil. Add passata to remaining oil, mix and use to coat the dough. Top with cheese then mushrooms.
Bake in the oven for 8 minutes. Switch the oven to grill and cook for a further 2 minutes, or until golden and the cheese is bubbling. Slice and serve.