Grease a springform pan with a tube bottom insert (22 cm Ø) and sprinkle with breadcrumbs. Roughly chop the walnuts. Quarter the apple, cut it crosswise into thin slices and immediately sprinkle with lemon juice
Cream fat, sweetness, aroma and lemon peel. Alternately add eggs and approx. 3 tbsp. flour. Mix the rest of the flour and baking powder and stir in alternately with the milk. Fold in 3/4 each apple and nuts
Spread the dough into the mould. Sprinkle the rest with apple and nuts. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/gas: level 2) for 40-45 minutes. Leave to rest in the pan for about 20 minutes. Turn out, let cool on a cake rack
Well packed, the cake stays juicy for 2-3 days. Or wrap in aluminium foil in portions and freeze