Mix flour, baking powder, 100 g sugar, salt and vanillin sugar. Add quark, oil and milk. Knead to a smooth dough with the dough hooks of the hand mixer. Knead again briefly with your hands. Grease a baking tray (32 x 39 cm) and roll out the dough in it. For the icing, mix sour cream, eggs, 75 g sugar and sauce powder with the whisks of the hand mixer.
Peel and halve the pears. Remove the core and cut the halved pears several times at the top. Spread on the dough and pour the icing over it. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 40 minutes. Remove from the oven, place on a cake rack and let cool. Cut into pieces and dust with icing sugar