Blueberry Sponge Cake Roll

Dough:

1. Preheat the oven to 170 ° O / bottom heat. Line a small sheet (25 x 38 cm) with baking paper. Spread out a larger kitchen towel and sprinkle with sugar. Have another kitchen towel ready. Possibly make the Cake Flour (in stock) see link.
2. Separate eggs. Beat the egg yolks with half of the powdered sugar until whitish and frothy. Add water, whip. Add oil, whip up (please really do both one after the other!). Pour in the vanilla flavor and stir in the flour on the lowest level. Then whip everything up again at the highest level for 10 minutes (with a food processor would be ideal because you can do something else at the same time).
3. If necessary, whip the egg whites until stiff. When it starts to set, add the powdered sugar little by little and then continue whipping until it shines and there are firm tips when you pull out the paddle. Then fold the firm egg whites into the dough in several portions.
4. Spread 100 g of the slightly frozen blueberries on the tray and carefully pour the dough over the top. Smooth out gently with a dough palette and place the tray in the oven on the 2nd rail from the bottom. The baking time is 14 minutes. It should only get a hint of color.

Filling and sheathing:

1. Put the remaining 200 g blueberries with powdered sugar and orange blossom water (alternatively orange or apple juice) in a taller container and puree finely with a hand blender. The frozen berries make it a bit tough at first, but more fluid than so-called lightning ice. Then mix this mass vigorously with quark, sour cream and lemon juice and finally stir in the instant gelatine.

Completion:

1. Immediately take the tray out of the oven after the above baking time and turn the sheet of dough out onto the cloth sprinkled with sugar. Place the 2nd (but previously well moistened) kitchen towel on the baking paper that is now on top and leave it there for a few minutes. Then take it off again and carefully peel off the baking paper. Now brush the dough sheet with the berries with about half of the blueberry quark and then roll it up from one narrow side using the cloth underneath. The seam should be below at the end. Transfer the roll to a firm surface, spread generously with the quark mixture and decorate as you wish. Then place in the refrigerator for about 1.5-2 hours. Any quark leftovers just like that.

Cake Flour:

1. This flour mix is ​​mainly used in American, but also Asian pastries and here too, in this sponge cake dough. Its preparation differs in some ways from what is known in our regions. With it, however, you can be 100% sure that it will always remain elastic, that it will not have any firm edges and that it will always roll well.
2. Here are two special flour mixtures for the American bakery in stock: –