Preheat oven to 350
Beat butter and cream cheese at medium speed with an electric mixer until creamy. Gradually add sugar, beating until light and fluffy. Add eggs, one at a time, beating just until blended.
Combine flour and next 3 ingredients; gradually add to the wet mixture, beating at low speed just until blended. Add in bananas, and vanilla just until mixed. Then with a spatula gently fold in blueberries. Spray two 8x4 loaf pans and spoon in the batter.
Bake for 1 hour or until a long wooden pick inserted in center comes out clean . Cool bread in pans on wire racks for 10 minutes.