Beat the egg yolks and sugar until fluffy. Sift together the flour and baking powder and work them into the egg mixture by hand to make a crumbly dough. Then rub in the butter and finally the salt. Divide the dough into 14 parts and roll into balls. Place the balls in the freezer until chilled. Place the balls in a greased muffin pan and bake at 160°C for about 25 minutes. Make indentations about 1 cm deep in the biscuits, for instance using the bottom of a liqueur glass. Blackcurrant compote: Simmer the blackcurrants with the sugar until they burst and the compote has thickened slightly, about 10 minutes on a medium heat. Blackcurrants are rich in pectin and will continue thickening as they cool. Turn out the biscuits and fill with the compote. Serve on their own or lukewarm with a scoop of vanilla ice cream.