Briefly mix the flour with powdered sugar, soft butter, 1 egg and salt. Then work quickly with your hands into a smooth dough. Wrap in foil and leave to cool for about 30 minutes.
Peel, quarter and core the pears. Score the curved side several times. Drizzle the pears with lemon juice.
Mix the sugar and sour cream, 3 eggs, sauce powder and vanilla macr together.
Roll out the dough on a floured work surface into a circle (32 cm) and place in a tart pan (28 cm). Press the edge down, prick the bottom several times with a fork.
Pat the pears dry and place on the bottom. Pour the glaze over it. Bake in the preheated oven at 175 ° C (fan oven 150 ° C) on the bottom rack for about 50 minutes. Let cool on a wire rack.