Cream together sugar, and peanut butter. Add biscuit mix, egg and milk. Mix well. Spoon into greased and floured 20 cm square pan. Drop jam by teaspoonfuls on top of batter. Cut through batter with knife to marble jam through the cake. Bake at 190ºC degree oven 30 minutes. Cut into nine squares. Serve warm or cold. Reprinted with permission from _Just Cakes_ From the C and H Sugar Kitchen Electronic format by Karen Mintzias