For the dough, knead margarine, sugar, flour and 2 tablespoons of cold water into a smooth dough. Form dough into a ball, wrap in foil and chill for about 30 minutes. Wash the nectarines and cut into slices from the stone.
Select the blueberries, wash and drain well. Mix fruit, jelly and starch loosely.
Roll out the dough between 2 sheets of baking parchment round (approx. 32 cm Ø). Remove the upper sheet of paper and use the lower sheet to place the dough in a greased and flour-sprinkled tart mould (approx. 26 cm Ø) with lift-off base.
Remove baking paper and press the dough lightly. Use your fingers to form the upper edge of the dough slightly wavy.
Sprinkle the base with almonds. Spread the fruit in the mould. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 40 minutes. Take the tart out of the oven and let it cool down.