Insane, sprinkled mug cake with apples in 10 minutes

Ingredients

2 ½ kg apples (e.g. Boskop)
350 g sugar
3 tbsp sugar
2 tsp cinnamon
1 lemon
400 g soft wheat semolina
400 g wheat flour
3 tsp baking powder
220 g cold butter
Icing sugar for sprinkling