Step 1: Prepare the Cake Batter

1. Preheat the Oven: Set your oven to 350°F (175°C). Grease and flour a bundt pan.
2. Cream Butter & Sugar: In a large mixing bowl, beat together the softened butter and granulated sugar until light and fluffy (about 3-4 minutes).
3. Add Eggs & Vanilla: Beat in the eggs one at a time, then mix in the vanilla extract and sour cream until well combined.
4. Combine Dry Ingredients: In a separate bowl, whisk together flour, baking powder, baking soda, and salt.
5. Mix Wet & Dry Ingredients: Gradually add the dry ingredients to the wet mixture, mixing until just combined.
6. Fold in Blueberries: Gently fold in the blueberries, being careful not to break them.

Step 2: Bake the Cake

1. Pour the Batter: Spread the batter evenly into the prepared bundt pan.
2. Bake: Place in the oven and bake for 55-60 minutes, or until a toothpick inserted into the center comes out clean.
3. Cool the Cake: Let the cake cool in the pan for 10 minutes, then invert onto a wire rack to cool completely.

Step 3: Make the Vanilla Glaze

1. Mix the Glaze: In a small bowl, whisk together powdered sugar, milk, and vanilla extract until smooth.
2. Drizzle Over Cake: Once the cake is completely cool, drizzle the glaze over the top.