In a large bowl, combine flour, sugar, baking powder and salt.
Cut in butter until mixture resembles coarse crumbs. Stir in walnuts.
In a small bowl, beat eggs, milk and vanilla; stir into dry ingredients just until moistened.
Gently fold in blueberries.
Pour into two 9-in. X 5-in. X 3-in. loaf pans.
Bake at 350 degrees F for 65-75 minutes or until the bread tests done. Cool in pan for 10 minutes until removing to a wire rack.