In a large mixing bowl, beat cream cheese with electric mixer on medium-high speed 3 to 4 minutes or until light and fluffy. Gradually beat in 1 cup sugar, beating for 2 to 3 minutes or until mixture is completely smooth, scraping sides of bowl. Reduce speed to medium, beat in rum (if you like), vanilla, and nutmeg. Add eggs all at once; beat on low speed until just combined. Stir in eggnog.