1 Cream 1/4 of the butter and the brown sugar until fluffy. Beat in egg and molasses.
2 Mix flour with cinnamon, ginger, and baking soda. Add to creamed mixture alternately with the buttermilk. Pour batter into an 8 or 9 inch microwave safe glass pan.
3 Microwave for 4 to 5 minutes on medium. Rotate 4 times while cooking. Microwave 2 to 3 minutes on high. Cake is done when a toothpick inserted into the middle comes out clean. Serve warm or cold with Lemon Sauce.
4 To Make Lemon Sauce: Combine the white sugar and cornstarch. Stir until well mixed; add water. Microwave 2 to 3 minutes. Stir every 30 seconds, until mixture has thickened and boiled for 30 seconds. Watch carefully so that it does not boil over. Add the remaining 2 tablespoons butter, lemon zest, and lemon juice. Serve warm or cold.