Combine the flour, sugar, baking soda, baking powder and salt in a large mixing bowl. Add in the walnuts; stir well. Lightly beat eggs in medium bowl with wire whisk. Add milk, jam, melted butter, and vanilla. Beat until well blended. Add chocolate and milk mixtures to flour mixture. Stir just until moistened. Pour into prepared pan. Bake 50-60 minutes or until toothpick inserted into center comes out clean. Cool on rack for 10 minutes, remove from cans and cool completely on wire rack.