Let the dough rest for about 10 minutes at room temperature. Grease depressions of a muffin tray (12 depressions). Cut 12 strips (approx. 4 x 12 cm) from baking paper and line each tray with them. Unroll the dough and roll it up again without the paper on which it lies. Cut into 12 slices. Press each slice flat on some flour and roll out round (approx. 11 cm Ø). Place the dough circles in the hollows, press them down and chill for about 30 minutes.
For the apple filling, wash apples, quarter them, remove seeds and cut into small cubes. Heat butter, 3 tbsp. sugar and lemon juice until the butter has melted. Simmer covered apples for about 3 minutes. Drain on a sieve, collecting the syrup.
For the cream, bring milk and vanilla pulp to the boil. Mix 150 g sugar, 1 tablespoon flour and 1 pinch of salt. Sprinkle into the milk while stirring vigorously. Bring to the boil again. Remove the pot from the stove. Let the mixture cool down a bit. Whisk egg and 3 egg yolks and stir into the cream.
First spread the apple filling, then the cream into the dough hollows. Bake in a hot oven (electric cooker: 225 °C/circulating air: 200 °C/gas: see manufacturer) for approx. 10 minutes. Mix the almonds with the collected syrup. Spread on the tartlets and bake for about 10 minutes. Allow to cool briefly and lift out using the paper strip. Dust with icing sugar.