Dain bottled boysenberries, save liquid. Mix lemon juice with liquid; add water, if necessary, to make 1-1/4 cups. Cream butter and sugar together. Add eggs and beat well. Combine flour, baking powder, baking soda and salt; add alternately with boysenberry liquid and milk; beat until smooth. Pour into buttered baking dish. Spread drained berries on top. Sprinkle with sugar. Bake at 375°F for about 40 minutes.