Preheat your oven to 350°F (175°C) and thoroughly grease a 6-cavity mini bundt pan with butter and flour or baking spray.

In a medium bowl, whisk together the flour, baking powder, and salt.

In a large bowl, cream the softened butter and granulated sugar together until light and fluffy, then beat in the eggs one at a time, followed by the vanilla extract, lemon zest, and sour cream.

Gradually mix the dry ingredients into the wet mixture until just combined, then gently fold in the blueberries with a spatula.

Divide the batter evenly among the mini bundt cavities, filling each about three-quarters full.

Bake for 20-25 minutes, or until a toothpick inserted into the cake comes out clean.

Let the cakes cool in the pan for 10 minutes before transferring them to a wire rack to cool completely.

Whisk the powdered sugar and lemon juice together to create a smooth glaze, then drizzle over the cooled cakes before serving.