- 8 ounces Pastry flour (plus more for dusting)
- 1 pinch Dry yeast (about 5 grams)
- ¾ cup Milk (low-fat)
- 3 tablespoons Sugar (about 60 grams)
- 9 ounces green grapes
- 9 ounces elderberries
- 1 tablespoon Butter (about 15 grapes)
- 4 Eggs
- 5 ounces Sour cream
- 5 ounces Quark
- 1 pinch Vanilla sugar
Mix flour and yeast thoroughly in a bowl. Heat the milk until lukewarm and add 2 teaspoons sugar. Mix into a smooth dough with a hand mixer.
Let rise, covered for 30-40 minutes in a warm place until the dough has doubled.
Meanwhile, rinse grapes and elderberries, drain well and pluck from the stems.
Knead dough again briefly with your hands. Roll out on a floured surface to a round, about 32 cm (approximately 12 inches) in diameter.
Grease a tart pan (32 cm or approximately 13 inches in diameter) with butter. Fit dough into pan, pressing it into edge.
Distribute fruit over the dough. Beat the eggs, sour cream, quark, remaining sugar and vanilla sugar in another bowl with the hand mixer and pour filling over the fruit.
Bake cake on bottom rack of preheated oven at 180°C (fan 160°C, gas: mark 2-3) (approximately 350°F) until filling is set in the middle, 40-45 minutes. Cool completely in pan on a wire rack before serving.