Melt butter, cool if necessary, knead with flour, sugar, egg yolk and lemon peel to form crumbs.
Press half of the mixture into a springform pan (26 cm diameter).
Cook pudding from milk and pudding powder. Stir the poppy seeds into the pudding, tablespoon at a time.
Fold in the drained mandarins and egg whites and place on the crumble base and sprinkle with the remaining crumble.
Bake in a preheated oven at 200 ° C for about 1 hour. Cover after 30 minutes or switch down to 175 ° C.
Tip:
Instead of baking poppy seeds, you can also cook 400 g ground poppy seeds with 125 g sugar in pudding. You can replace the mandarins with apricots cut into wedges.