Preheat oven to 350 degrees. Liberally spray a 12-cup bundt pan with baking spray with flour. (Make sure to liberally spray, mine stuck a little.) Cream together butter and sugar for 5 minutes, until very light and fluffy.
Add eggs, one at a time until incorporated. Add vanilla and rum.
Add 1/3 of the flour mixture.
Add half of the eggnog. Mix on low until incorporated, then add the next addition. Repeat until everything is added.
Add half of the batter to the prepared pan. With the remaining batter add the cinnamon, nutmeg, allspice, and cloves. Mix by hand until combined.
Spoon the spiced batter over the plain batter and use a knife to swirl together. Bake for 50 to 55 minutes, or until a toothpick comes out clean.
Cool in pan for 10 minutes, then turn out onto a wire rack and cool completely.
To make the glaze, whisk together powdered sugar, eggnog, rum, and vanilla.
Drizzle over cooled cake. Top with fresh nutmeg.