Cream butter and sugar; beat in eggs one at a time. In another bowl, add milk and lemon juice to bananas then combine with butter mixture. Sift together flour, baking powder, salt and soda, and add to mixture, beating on low speed just until blended. Stir in the nuts briefly. Bake in a greased 8-1/2x4-1/2 inch pan at 350 F. for 45 minutes.