Heat the oven to 180°C (fan) / 200°C / gas 6.
Grease the cups of the muffin pan with butter and scatter with cream of wheat.
Cream together the butter and sugar and beat in the eggs one by one.
Stir in the quark, corn starch, vanilla extract, baking powder, lemon zest and salt.
Spoon the batter into the pan cups and bake for approx. 30 minutes until golden brown.
Remove from the oven, let cool for a few minutes then remove from the pan and cool on a wire rack.
Melt the chocolate and drizzle over the muffins.
Serve dusted with icing sugar.