12 Line the troughs of a muffin tin with paper baking cups. Roughly chop the walnuts. Wash apples, dab dry and grate coarsely, except for the core. Mix flour, baking powder and 125 g sugar in a bowl. Whisk egg, milk, grated apple and oil. Add the flour mixture and mix briefly. Fold in walnuts, except 1-2 tbsp.
Spread the mixture into the bowls. Add the remaining walnuts. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 15 minutes. Beat the egg whites until stiff, add 150 g sugar and continue beating until the mixture is firm and shiny. Pour the mixture into a piping bag with a perforated spout. Remove the muffins, sprinkle meringue mixture over them and bake for 8-10 minutes until the meringue is lightly browned. Take out the muffins and let them cool down
Waiting time approx. 1 hour