Heat the oven to 350 degrees. Butter an 20 cm square pan, set aside. Mix all ingredients together except the jam. Press 2 cups of the mixture into the bottom of the prepared pan. Spread the jam to within 1 cm of the edge. Sprinkle the remaining crumb mixture over the top and lightly press it into the jam. Bake 35 to 40 minutes and allow to cool on a wire rack before cutting into 2 x 1- half inch bars.