From Sara Delano Roosevelt’s Household Book
Put a little powdered sugar into a tumbler
A teaspoonful or more of brandy
The yolk of a pastured egg
1/2 a tumblerful (3/4 cup more-or-less) of fresh, cream-top milk,
then fill up with cracked ice not too fine & shake well together in a shaker (a big tin tumbler & a strong glass tumbler).
Strain it into a clean tumbler & put on top a suspicion of freshly-grated nutmeg.
-James Roosevelt with son Franklin Delano