Preheat oven to 350°F. Grease two 9x5 loaf pans.
In a large bowl, cream together butter, cream cheese, and sugar until smooth. Mix in vanilla and eggs.
Stir in flour, baking powder, and salt until just combined. Gently fold in blueberries.
Divide batter evenly between prepared pans.
Bake for 50 minutes, until a toothpick inserted in center comes out clean.
Let cool 15 minutes before removing from pans.
Slice and enjoy! Bread stays fresh at room temp for up to 3 days, or can be frozen for up to 3 months.