Cut 125 g butter into pieces. First knead 65 g sugar, 250 g flour, egg yolk and butter with the dough hooks of the hand mixer, then work into a smooth dough with your hands. Wrap the dough in foil and chill for about 30 minutes. Wash the mint, dab dry well and remove the leaves. Mix the mint leaves and 50 g sugar in the universal chopper. Wash and halve the nectarines, remove stones.
Cut halves into 4 slices each. Sprinkle with lemon juice and put aside covered. Roll out the dough (approx. 30 cm Ø) and line a greased tart tin (27 cm Ø) with it. Cut off any protruding edges. Line the mould with baking paper, fill in pulses. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes. Knead 90 g butter, 120 g flour, baking powder and 35 g sugar. Add buttermilk and chill. Warm up the jam and pass through a sieve. Put the lady fingers in a freezer bag and crumble with the cake roll. Remove the base from the oven. Remove baking paper and legumes.
Knead 90 g butter, 120 g flour, baking powder and 35 g sugar. Add buttermilk and chill. Warm up the jam and pass through a sieve. Put the lady fingers in a freezer bag and crumble with the cake roll. Remove the base from the oven. Remove baking paper and legumes. Sprinkle the sponge cake crumbs on the base. Place nectarine slices in a circle from the outside to the inside and spread with the jam. Spoon buttermilk mixture onto the nectarines with a teaspoon. Bake at the same temperature for another 15 minutes. Remove the tart from the oven and let it cool down. Sprinkle with mint sugar before serving
Sprinkle the sponge cake crumbs on the base. Place nectarine slices in a circle from the outside to the inside and spread with the jam. Spoon buttermilk mixture onto the nectarines with a teaspoon. Bake at the same temperature for another 15 minutes. Remove the tart from the oven and let it cool down. Sprinkle with mint sugar before serving