Mix 125g soft butter and 3/4 cup sugar with the lemon zest. Stir in an egg and the pulp of a vanilla pod. Turn the blueberries in a tablespoon of flour. Mix the remaining flour with baking powder and a pinch of salt and add to the butter mixture. Add buttermilk and stir. Then carefully fold in the blueberries.
Grease a small baking dish and pour the batter into the mold. Sprinkle the dough with 2 tablespoons of sugar and bake in the preheated oven to 175 degrees top / bottom heat for about 60 minutes until no more dough sticks to the wooden skewer or the dough forms a golden brown crust. Let cool down for 15 minutes.
Tip:
Serve warm with a scoop of vanilla ice cream per serving.