Place the puff pastry slices next to each other and allow to thaw. Mix sour cream, eggs and sugar. Stir in pudding powder, espresso powder and cocoa. Place the puff pastry slices on top of each other and roll out thinly. Cut out a total of 8 circles (approx. 11 cm Ø) from the dough. Place the dough slices on top of each other again, roll out and cut out the remaining circles.
Grease brioche cups (100 ml content) and line with dough. First put 3-4 blueberries on each bottom, then fill in cream. Bake the tartlets in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 15-18 minutes. Remove and let cool on a cake rack. After about 15 minutes, remove the tartlets from the ramekins. Decorate the tartlets with remaining blueberries
Waiting time approx. 1 hour