Preheat oven to 350°F (175°C). Grease and flour a 9x5 inch loaf pan.

In a large bowl, cream together the butter and cream cheese until smooth.

Beat in the sugar, then add the eggs one at a time, mixing well after each addition.

Stir in the vanilla extract.

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

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Gently fold in the floured blueberries.

Pour batter into the prepared loaf pan and bake for 50-60 minutes, or until a wooden skewer inserted into the center comes out clean.

Let the bread cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.