For the apple roses, wash and halve the apple. Remove the core with a ball cutter. Place with the cut surface facing down. Cut the fruit halves into slices about 2 mm thin. Put into a bowl with lemon juice and about 5 tbsp. water.
Drain the blueberries in a sieve, collecting the juice. Fill up with water at 1⁄2 l liquid. Heat up with 100 g sugar (do not boil!). Steam apple slices in it in portions for about 15 seconds until they are just soft and pliable.
Lift out with a skimmer, drain in a sieve.
Line a baking tray with baking paper. Place approx. 1⁄4 apple slices next to each other and overlap to form a row. Let them cool down. Roll up each row of apples from one side to a rose.
Preheat oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer). Grease a box form (25 cm long; approx. 1 1⁄2 l capacity) and sprinkle with breadcrumbs. For the dough, whip 125 g butter, 125 g sugar, vanilla pulp, 1 pinch of salt and lemon zest until creamy.
Stir in the eggs one by one. Mix 200 g flour and baking powder. Stir into the butter-sugar cream with milk. Fold in the berries.
Smooth the dough in the form. Dip apple roses with the underside in flour and press them carefully into the dough, for example to 1⁄3. Bake in a hot oven for approx. 45 minutes (stick test). Remove from the oven.
Leave to cool for about 30 minutes. Carefully turn out of the mould.