In a medium saucepan, combine the whole milk, ground cinnamon, ginger powder, and nutmeg. Heat over medium heat, stirring occasionally, until the mixture is steaming and the spices are fragrant. Avoid boiling.

In a separate large bowl, whisk together the egg yolks and sugar until the mixture is light and fluffy.

Gradually pour about 1 cup of the warm milk mixture into the egg yolk mixture, whisking constantly to avoid curdling. Once combined, pour the tempered egg yolk mixture back into the saucepan with the rest of the milk mixture.

Cook the combined mixture over low heat, stirring continuously, until it thickens slightly and coats the back of a spoon, around 5-10 minutes. Make sure it doesn’t boil, we want to get it to a temp of 160F. and use a thermometer to keep it below 160°F (71C).

Pour the thickened mixture through a fine-mesh sieve into a pitcher or bowl to remove any bits of cooked egg or spices.

Stir in the heavy cream, vanilla extract, and alcohol if using. For a lighter texture, whip the optional egg whites to soft peaks and fold them into the mixture for added frothiness.