1. Cream butter and sugar until light and fluffy; add eggs and beat well.
2. Dissolve baking soda in buttermilk. Combine dry ingredients. Add buttermilk mixture and dry ingredients to cream mixture; stir well.
3. Stir in jam. Spoon mixture into a greased 8x8 inch square baking pan. Bake in a 350 degree oven for 35 to 40 minutes or until done. Serve with vanilla ice cream. May add an additional teaspoon of jam on top just before serving.