Grate nuts with the Bircher grater in the TRANSFORMA® drum grater. Mix with flour, rolled oats, sugar and salt. Spread the butter in small flakes on top and work into crumbles with your hands.
Preheat the oven to 180°C.
Pluck basil leaves from stems, chop finely. Wash the Granny Smith, quarter it, remove the seeds and grate it with the birch grater of the TRANSFORMA® drum grater.
Mix both with sugar and lemon juice and divide among 4 ovenproof glasses. Put the crumble on top and bake in the oven for about 30 minutes until golden brown.
Tip: The crumble is easy to vary, instead of basil use mint or tarragon or season classically with raisins and cinnamon.