Preheat oven (electric cooker: 220 °C/circulating air: 200 °C/gas: see manufacturer). Line a baking tray with baking paper. Separate the eggs for the sponge cake. Beat the egg whites with 1 pinch of salt until stiff, adding 100 g sugar.
Add the egg yolk and continue beating briefly. Mix the cake glaze with 3 tbsp. water and fold into the egg whites. Fold in flour with a whisk. Spread the dough on the baking tray. Bake in a hot oven for about 8 minutes.
Remove and immediately turn onto a tea towel sprinkled with sugar. Carefully remove the baking paper. Roll the sponge loosely from the long side using the tea towel. Let it cool down.
For the cream, meanwhile, wash and clean the strawberries and, depending on their size, cut them into eighths or quarters. Stir quark with 2 tablespoons fruit spread and sugar until smooth. Whip cream until stiff and fold in. Fold approx. 3 tbsp. fruit spread into the cream in streaks.
Unroll the sponge cake. Spread the rest of the fruit spread on the former baking paper side and spread approx. 2⁄3 cream on top, leaving an approx. 5 cm wide edge on the back long side. Spread about half the strawberries on the cream.
Roll up the sponge cake using the cloth. Place the roll on a plate and spread the rest of the cream loosely. Decorate with remaining strawberries. Chill briefly until serving.