Wash apples, dab dry and remove the core with an apple corer. Cut apples into 8 slices of about 1 cm thickness. Bring 5 tablespoons lemon juice and 1/4 litre water to the boil in a wide saucepan.
Steam apple slices in it at low heat for about 5 minutes. Stir cream cheese and milk until smooth. Stir in poppy seeds, season with salt, pepper and remaining lemon juice. Drain apple slices and let them cool down a little.
Cut the pumpernickel diagonally in half to form triangles. Wash and drain the oak leaf salad. Pour poppy seed cream cheese into a piping bag with a large star-shaped spout and squirt onto the apple slices. Arrange apple slices with the oak leaf salad and pumpernickel on 4 plates and serve.