Preheat the oven to 350°F. Move the oven rack to the lower ⅓ of the oven. Grease and flour a tube or bundt pan or spray with baking spray. Set aside.
Sift together the flour, baking powder, salt, nutmeg and cinnamon.
In the bowl of a stand mixer, cream together butter sugar, rum and vanilla extracts. Beat for 2-3 minutes until fluffy and fully combined.
Add the eggs one at a time beating well after each addition. Stop and scrape the sides of the bowl periodically.
Gradually add the sifted dry ingredients alternately with eggnog. Beginning and ending with flour. After all has been added, increase the speed of the mixer and beat just until fully combined. Stop and scrape the sides of the bowl as needed.
Spread evenly into the prepared pan. Bounce the pan on the counter to settle batter.
Place into the oven and bake for 1 hour 10-15-minutes or until a cake tester inserted into the center shows moist crumbs. Check halfway through and lay a piece of aluminum foil on top to prevent over browning, if needed.
Cool in the pan for 15 minutes then remove and place onto a cooling rack to cool completely. Dust with powdered sugar or glaze, if desired.
To glaze: In a small bowl whisk together powdered sugar, eggnog butter and rum extract. (May use 1-2 tablespoon dark rum in place of extract, if preferred.) Add additional eggnog until your desired thickness is reached.
Drizzle over cake and dust with nutmeg. Store chilled.