Add the lemon juice, simple syrup, egg whites and whiskey to a cocktail shaker.
(If you are not using egg whites, skip this step.) Seal the shaker and do a dry shake, which means shake everything without ice. Shake vigorously for at least a full minute to get the most stable foam.
Add ice to the shaker and shake again (a wet shake). You only need to shake about 15 to 20 times.
Add ice to your serving glass.
Strain the drink into the glass. If you have a fine mesh strainer, use it here along with the regular cocktail strainer. This is called "double straining".
Carefully pour the red wine onto the back of a bar spoon and into the glass. This will create a floating layer of wine at the top of the drink.
Serve and enjoy!
Notes
Rye is typically used, but bourbon whiskey also works well in this drink.
Egg whites are optional, but create a nice foam on top as well as rounding out the flavors.
You can use pasteurized egg whites or fresh, and both will be able to create the foam. If you use pasteurized, dry shake for 2 minutes instead of 1.
If you have a hard time shaking, use a milk frother instead of doing the dry shake.
Use a vegan cocktail foamer or aquafaba in place of egg whites for an eggless option that still has the foam.
Dry red wine works best in this drink. The less sugar the wine has, the better it will float. Try a Malbec or Pinot Noir.
Garnish: you can optionally add a lemon peel to the rim of the glass, or use a cocktail cherry on a pick for an extra garnish.