Mix 275 g flour, 1 pinch of salt and 2 tablespoons of sugar. Add butter in pieces and grate everything into crumbles with your hands. Add 4-5 tablespoons of ice-cold water and knead to a smooth dough. Cover the dough and chill for about 30 minutes.
Select the blueberries, wash carefully and drain well. Mix with jam. Preheat oven (electric cooker: 200°C/circulating air: 175°C/gas: level 3).
8 wells of a muffin tray (12 wells) grease well. Roll out the dough onto some flour to a thickness of 2-3 mm. Cut out 8 circles (12 cm Ø each) and line the greased troughs with them. Roll out the remaining dough again.
Grate the cheese and sprinkle on the crêpes. Bake in the preheated oven (electric cooker: 200°C/circulating air: 175°C/gas: level 3) for approx. 15 minutes. Wash the chives, shake dry, cut into fine rolls and sprinkle on top.
Sprinkle 1 tsp. breadcrumbs into each of the muffin troughs. Spread blueberries on top. Whisk the egg. Brush the edges of the dough circles with egg yolk. Place on the blueberries and press the rim well down.
Brush with the remaining egg and sprinkle with 2 tablespoons of sugar.
Bake in the oven on the lowest shelf for about 30 minutes. Let cool briefly. Then loosen at the edges and remove from the trays. Leave to cool. Serve lukewarm or cold. Serve with whipped cream.