Preheat your oven to 350°F (175°C) and grease a loaf pan.

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

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

Stir in the sour cream and vanilla extract until well combined.

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

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

Gently fold in the blueberries, being careful not to break them.

Pour the batter into the prepared loaf pan and smooth the top.

Bake in the preheated oven for 55-60 minutes or until a toothpick inserted into the center comes out clean.

Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.