Set oven to 350F Spray a 9x5 loaf pan lightly with cooking spray, and then, if you like, line it with parchment paper leaving the ends long so you can lift it out when it's cool. Cream the butter and the sugar until fluffy. Beat in the vanilla and the egg. Blend in the applesauce. Sift together the flour, baking soda, salt, and spices and then add it to the bowl slowly. When everything is incorporated, turn the batter into your pan and smooth it out. Bake for about 55 minutes, or until it is risen and a toothpick comes out clean. Loaf pans and ovens can vary greatly, use your common sense to tell you when your cake is done. Check it early. Let cool completely on a rack before frosting. To make the frosting, beat the cream cheese with the vanilla and then add 2 1/2 cups of the sugar and beat until smooth and creamy. Add a little more sugar if it's not as thick as you like. Spread a thick layer of the frosting over the gingerbread. Dust with freshly grated nutmeg.