Chill your base. Use cold eggnog and a frozen banana.
Cold ingredients blend thicker and taste brighter.
Load the blender. Add eggnog, frozen banana, Greek yogurt, cinnamon, nutmeg, vanilla, and a pinch of salt. Start with no added sweetener.
Blend until smooth. Begin on low, then move to high for 20–30 seconds. Add ice and blend again until creamy.
Taste and adjust. If you want it sweeter, blend in maple syrup or honey 1 teaspoon at a time.
For thinner texture, add a splash more eggnog.
Serve cold. Pour into a chilled glass, top with whipped cream if you like, and finish with a dusting of nutmeg.