Mix 375 g flour, baking powder, 75 g sugar, 1 pinch of salt and nutmeg in a bowl. Add butter in pieces and 150 g cream. First knead quickly with the dough hooks of the mixer and then with your hands to a smooth dough.
Cover and chill for about 15 minutes. Then leave to rest at room temperature for approx. 30 minutes.
Select blueberries, wash if necessary, drain. For the compote, put 2/3 of the berries, 2 tablespoons of sugar, lemon juice and 3 tablespoons of water in a pot. Bring to the boil. Stir starch with 1 tbsp. water until smooth.
Tie compote with it. Let it cool down.
Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Line a baking tray with baking paper. Quickly knead the rest of the blueberries into the dough with floured hands. Pour the dough onto the baking tray and shape into a square of approx. 20 x 20 cm.
Using a pizza wheel, score three times lengthwise and twice crosswise so that 12 pieces are pre-portioned. Bake in a hot oven for 40-45 minutes.
Take out and let it cool down a little. Whip 200 g cream until stiff, mix lightly with compote. Dust biscuits with icing sugar and serve lukewarm with cream-blueberry compote.