Cream together butter and sugar. Ads eggs one at a time, beating well.
Mix together flour, baking powder and salt.
Add to mixture alternately with 1/2 cup of milk, sugar and egg mixture.
Add grated rind of lemon. Carefully fold in blueberries. Bake at 350 F or 175 C for 60 minutes or until testing done.
Cool 5-10 minutes. Mix 1/2 cup of sugar and juice of lemon and allow to sit for a while before pouring over bread in the pan.
Let stand 30 minutes before removing from pan.