Preheat oven to 350 degrees. Mix together eggnog, beaten egg and oil. Stir in flour, sugar, baking powder and salt. Fold in pecans and maraschino cherries.
Spread into two 8x4-inch bread pans that have been sprayed with non-stick cooking spray.
Bake at 350 degrees for 45 minutes or until done. Cool in pans 10 minutes; turn out on rack to finish cooling.
For Icing: In 1-quart saucepan, melt margarine. Blend in confectioners' sugar and flavoring. Stir in 1 tablespoon hot water at a time, not using more than 4 tablespoons total. Add only enough hot water to make a nice spreading consistency. Spread this over top of both cooled loaves.
Decorate tops with additional cherries and pecan halves, if desired.