Preheat oven to 350 degrees. Grease an 8-inch square pan, and line with greased foil.
Combine the brown sugar, flour, baking soda, salt, and oats. Rub in butter using a pastry blender to form a crumbly mixture. Press 2 cups of the mixture into the bottom of the pan. Spread the jam to within 1/4-inch of the edge. Sprinkle the remaining crumb mixture over the top, and lightly press it into the jam.
Bake for 30-35 minutes or until lightly browned. Allow to cool before cutting into bars.