Knead the dough from the ingredients listed and refrigerate for at least 60 minutes. Roll up 2/3 of the dough thinly, cut out eight circles and line greased ramekins with them.
Mix apple puree with almond kernels and pour about 2 tablespoons of it into each ramekin.
Cut out eight lids from the remaining dough with an empty ramekin. Brush edges of dough with cold water, place dough lids on filled ramekins and press smooth. Place the ramekins in the preheated oven.
Bake at 175 °C for 20 to 30 minutes.
Loosen the edges of the still-hot tartlets with a kitchen knife, but let them cool in the ramekins.
Dust the tartlets with powdered sugar before serving.