• Preheat your oven to 350°F.
• In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter and sugar on medium speed for about 2 minutes, until the mixture is light and fluffy.
• Add in the eggs, vanilla, sour cream, salt, and baking powder. Mix for another minute until smooth, making sure to scrape down the sides of the bowl as needed.
• Turn the mixer to low and slowly add the flour. Mix just until the flour is incorporated—don’t overmix.
• Gently fold in the blueberries with a spatula.
• Lightly coat a 9–10 inch bundt pan with baking spray. For best results, spray just before adding the batter. Spoon the batter evenly into the pan and smooth out the top.
• Bake for 45–55 minutes, or until a toothpick inserted into the center of the cake comes out clean.
• Let the cake cool in the pan for 15 minutes, then carefully invert it onto a wire rack to cool completely.

For the Icing:

• In a medium bowl, whisk together the butter, powdered sugar, vanilla, and 1 tablespoon of milk until smooth. If you prefer a thinner consistency, whisk in an extra tablespoon of milk.
• Once the cake is mostly cooled, drizzle the icing generously over the top.