In a large bowl, sift together the flour, baking powder, salt, cinnamon, and nutmeg. Set aside.
In the bowl of a stand mixer, cream the room temperature butter until smooth. Add the sugar. Beat on medium speed until light and creamy, about 3-4 minutes.
Add in eggs, one at a time, beating well after each addition. Add in vanilla and rum extracts.
Alternating between the flour mixture and eggnog (starting and ending with the flour) add in both. Mix until smooth being careful to not over-beat the mixture (will result in a dense cake).
Spoon batter into a well greased and lightly floured 9-inch loaf pan. Bake for 50-55 minutes, until a toothpick inserted in center, comes out clean. Let cake rest in pan for 15 minutes before turning out onto a cooling rack and then cool it completely.
For the glaze, whisk together the powdered sugar and rum extract, adding egg nog until desired consistency has been reached. Spoon over cooled cake. Let glaze set up for a few minutes before cutting into the cake.
Cake best enjoyed within 2-3 days. Store the cake in an airtight container in the fridge.