Preheat the oven to 350°F (175°C). Grease the mini bundt cake pan.

In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

Stir in the buttermilk and vanilla extract.

In another bowl, whisk together the flour, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Spoon the batter into the prepared mini bundt cake pan, filling each mold about 2/3 full.

Bake in the preheated oven for 20-25 minutes, or until a toothpick inserted into the center comes out clean.

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

In a small bowl, whisk together the powdered sugar, milk, and vanilla extract until smooth.

Drizzle the glaze over the cooled mini bundt cakes before serving.