Potato Pizza with sage & onion

Directions

1. For the dough, mix together quark, milk, 4 tablespoons oil and 1/2 teaspoon slat in a bowl.
2. Mix together flour and baking powder, then add to the quark mixture and knead with dough hook of a hand mixer until smooth.
3. Peel and slice potatoes with a mandolin into very thin slices. (If desired, pre-boil the peeled potatoes in boiling water for 10 minutes and allow to cool.)
4. Peel the onion and cut into thin slices. Rinse sage, shake dry, pluck leaves and chop coarsely.
5. Mix potato and onion slices, sage and remaining oil in a bowl. Season with salt and pepper.
6. Divide the dough on a lightly floured work surface into 4 portions and roll our each into a round, about 23 cm (approximately 9 inches) in diameter.
7. Place 2 dough rounds on a parchment-lined baking sheet.
8. Top each round with 1/4 of the potato-onion mixture and bake on bottom rack of preheated oven at 225°C (fan 200°C, gas: mark 3-4)(approximately 450°F) for 15-20 minutes.