Preheat oven to 350F°. Grease and flour your mini bundt pan or spray with non stick cooking spray.
Add flour, baking powder, and salt to a bowl. Stir to combine and set aside.
Add the sugar, butter, and two eggs to a bowl. Mix until all ingredients just combined.
Add the buttermilk and mix into the batter.
Add flour, baking powder, salt, and mix until just combined.
Grate in some lemon zest and add the lemon juice; stir to combine.
Fold in the blueberries, putting in a few handfuls (about 1/2 cup). Fold in lightly with a spoon or spatula; don't stir or beat.
Place the batter in your prepared pan and place into the oven.
Bake for 16 - 24 minutes. Check at 16 minutes and then at 20 minutes using a toothpick.
Remove from oven and let bundt cakes cool for 5 - 10 minutes. Remove from the pan to a wire rack to cool completely.
Place the confectioners' sugar and lemon juice in a bowl. Whisk together and add more juice if needed.
Drizzle glaze over the top of the bundt cakes on the wire rack. Let the glaze set before serving.