For the dough, stir the butter or margarine with a hand mixer on the highest setting until smooth. Gradually stir in the sugar and vanilla sugar. Stir until a bound mass has formed. Gradually stir in the eggs (each egg about 1/2 minute). Mix the flour with the baking powder and cocoa, sift and stir in portions alternately with the milk on a medium setting. Finally stir in the crushed (grated) chocolate briefly.
Pour the batter into a prepared muffin tin and smooth it out. Put the tin on the wire rack in the preheated oven.
Top / bottom heat: approx. 180 ° C
Hot air: about 160 ° C
Gas: level 2 - 3
Baking time: about 25 minutes
Let the muffins stand in the mold for 10 minutes, then remove them from the mold and let them cool on a wire rack. Cut a lid from each muffin. Hollow out the base of the muffin with a teaspoon so that a 1 cm thick edge remains. Hollow out the lids a little too. Crumble the leftovers. Set aside a good 5 tablespoons of the crumbs for garnish.
For the filling, wash the strawberries, drain them well, remove the stems and cut into small cubes. Mix the sour cream with sugar and vanilla sugar with a whisk. Carefully fold in the strawberry cubes and the remaining pastry crumbs. Use a teaspoon to pour this mixture into the indentations of the base of the muffin like a mountain.
To brush the jam with water, bring to the boil in a small saucepan. Brush the pastry lids with it using a brush. Sprinkle the lid with the biscuit crumbs that have been set aside and press the crumbs down a little. Place the lids on the filling and chill the muffins for about 30 minutes.
The muffins can be garnished with strawberry slices before serving.
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