This is, basically, a very simple single-serving eggnog. Most shakers will hold a double or possibly even a triple recipe. Shaking it with ice helps it whip just slightly even without any cream.
If you want to make it even more festive, consider using maple sugar instead of powdered sugar. And, of course, being eggnog-adjacent you can use rum—probably dark—or brandy instead of bourbon.
It’s a great accompaniment to ringing in the New Year!
Dinner is never served until everyone present has at least three drinks. — Carl Randall (Life, Loves, and Meat Loaf)