Rinse the currant, drain well and remove from the panicles.
Grease a muffin tray or line with paper cups. Preheat the oven to 160 °C convection oven (or 180 °C top/bottom heat).
Mix sugar, vanilla sugar and egg until thick and creamy. Add oil and yogurt. Mix flour, baking powder and almonds and fold in briefly. Carefully fold in the currant.
Fill the muffin tin 2/3 full with batter. Bake for about 20-25 minutes. Let cool.
Meanwhile, for the frosting, sift confectioners’ sugar and stir with the lemon juice until smooth.
Spread the frosting on the cooled muffins and let dry before serving.