1. Preheat the oven to 180°C (350°F) and grease and flour a rectangular loaf pan. In a bowl, mix the flour, baking powder, vanilla sugar, and salt.
In the mixer bowl, beat the butter with the sugar until light and fluffy. Add the eggs one at a time, continuing to beat after each addition.
2. Pour in the milk and lemon juice. Gradually add the flour mixture, mixing well until the ingredients are just combined. In a small bowl, toss the blueberries with the 2 tablespoons of flour (this helps prevent them from sinking to the bottom of the cake). If the blueberries are completely dry, rinse them lightly and drain well so the flour sticks better. If you prefer to use frozen blueberries, use them directly from the freezer.
3. Gently fold the coated blueberries into the batter using a spatula. Pour the batter into the prepared pan and bake for 50 minutes, or until a skewer inserted into the center comes out clean. Let the cake cool in the pan for 10 minutes before turning it out onto a wire rack.
For the Lemon Glaze:
1. Whisk the powdered sugar with the lemon juice until you have a smooth glaze.
2. Pour the glaze over the cooled cake.
3. Garnish with extra blueberries and a few mint leaves, if desired.
