Use a basting brush to grease a bundt pan with butter or Crisco. Dust the entire pan with flour, rotating it and tapping the flour around until the entire surface is covered.Take your time on this step. It can mean the difference between a cake that releases perfectly or a cake that comes out of the pan in pieces.
Cream together butter and sugar. Add egg yolks one at a time; making sure that each one is completely incorporated before adding the next one.
Sift together dry ingredients. Add the dry ingredients to the creamed mixture alternately with eggnog.
In a separate bowl, beat egg whites until they form soft peaks.Using a rubber spatula, fold the egg whites into into the batter.
Spread the batter into the prepared bundt pan. Give the pan a couple of solid taps on the counter to make sure all those little ridges are filled in.
Bake 50-55 minutes, or until tester comes out clean. The cake will readily spring back, and the top of cake will likely be slightly cracked.
Remove the cake from oven and cool in the bundt pan no less than 10 minutes and no more than 15 minutes before it turning out.
Make the glaze while the cake is cooling in the pan before you turn it out.
Combine the sugar, butter, water, and nutmeg in a small saucepan. Bring to a boil over MEDIUM heat. Reduce to MEDIUM-LOW and simmer 5 minutes, stirring constantly.Remove the glaze from heat. Stir in rum and brandy (or rum flavoring and apple juice). (WARNING: Stand back a little when you you add the alcohol, or the alcohol cloud that is released may sting your eyes.)The glaze will be very thin.
To turn out the cake, place the cooling rack on the top of the bundt pan and flip it over in one fluid motion. The cake should immediately fall onto the rack.Prick top and sides of the cake all over with a few toothpicks or a thin skewer.
To glaze, start with very warm glaze and a very warm cake. The glaze will be very thin when you start, but will thicken slightly as you go. Use a pastry brush and take your time, or all the glaze will run off. Glaze the cake in layers, stopping for a minute between each layer, until the glaze is all on the cake.
Let cake cool at room temperature for 2-3 hours before serving.
Notes
If you typically make your cakes from a mix, be aware that this batter is much thicker than a standard box cake. Before the egg whites are folding in, it should be the consistency and texture of very soft cookie dough.If you are concerned about the alcohol being in your finished cake, don't be. It will all boil off immediately when you add it to the boiling hot glaze mixture. In fact, when you do this, stand back a little or the alcohol cloud from the burn-off may sting your eyes. (Voice of experience.)Eggnog Bundt Cake freezes well.