Pre-heat oven to 350 degrees F (175 degrees C). Lightly grease one 9 x 13 inch baking pan.

To make the crust, start by combining the flour and brown sugar in a large bowl. Then cut in vegetable shortening until mixture looks like coarse crumbs. Press evenly into the baking pan.

For the filling, beat the egg until thick and light colored. Next, beat in the baking soda. Lastly, stir in the sour cream. Mix until well blended

Pour the filling over the crust, and distribute chopped macadamia nuts evenly over the top.

Bake for 45 to 50 minutes, or until firm. Place the pan on a wire rack to cool. When cool, cut into bars.