Mix the milk, vanilla pudding powder, sugar and corn grits together in a small saucepan. Bring to the boil, stirring constantly, otherwise it will burn slightly, and then leave to cool in the refrigerator. When the mixture is lukewarm, fold in the blueberries with a spoon. Mix the quark and 1 egg together well. When the pudding mixture has cooled, mix with the curd.
Preheat the oven to 175 ° C top / bottom heat. Brush the puff pastry with the curd mixture and fold in. Brush the dough with egg yolk and sprinkle with a little water, then prick several times with a fork. Bake until golden brown for 20-30 minutes.
Tip:
The curd mixture is pretty runny. If you just put the strudel on a baking sheet, the strudel will separate and tear. If that bothers you, you can also put the strudel in a suitable shape.