Clean 400 g rhubarb, wash and cut into slices of about 0.5 cm thick. Cut the remaining rhubarb into small cubes. Mix starch with 2 tbsp. water. Caramelise 50 g sugar in a pot. Deglaze with nectar. Add the rhubarb slices and simmer for about 1 minute. Stir in the starch mixture and bring to the boil while stirring constantly. Put compote into a bowl. Let cool down for about 1 hour. Place the puff pastry slices next to each other and defrost at room temperature for approx. 10 minutes
In the meantime, chop the pistachios. Mix flour, 3 tablespoons of sugar, butter in flakes and pistachios first with the dough hooks of the hand mixer, then with your hands to crumble. Mix 5 tablespoons of milk, 3 tablespoons of sugar, vanilla sugar and pudding powder until smooth. Bring 250 ml milk and cream to the boil. Stir in the pudding powder and let it simmer for about 1 minute while stirring. Pour into a bowl, cover surface with foil and set aside
Cut the puff pastry slices in half crosswise. Grease a muffin tray (12 troughs). Press a puff pastry square into each trough, pressing the pastry corners outwards. Separate 1 egg. Set aside the egg white. Stir rhubarb cubes, egg and egg yolks into the cream. Spread the cream in the bowls. Add crumbles evenly. Brush excess puff pastry with egg white. In the preheated oven
Let the muffins cool in the tin on a cake rack for about 15 minutes. Remove from the tin and let them cool down. Serve with rhubarb compote