Chop the chocolate and melt with butter in pieces in a hot water bath. Let it cool down a little. Grease 4 ovenproof moulds (each containing approx. 200 ml) and sprinkle with sugar.
Beat the eggs, egg yolks and 60 g sugar with the whisk of the hand mixer for about 5 minutes until frothy. Stir in flour and melted chocolate.
Fill the moulds to about 3/4 with the chocolate mixture. Bake in a hot oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2) for 12-15 minutes.
In the meantime, blend the frozen blueberries, 1 tablespoon of sugar and lemon juice with a hand blender to a creamy ice cream. Serve immediately with the hot chocolate pudding. Do not be surprised: The inside of the pudding is still very creamy.