In a large bowl, combine whiskey, Luxardo Amaretto, Luxardo Aperitivo, lemon juice, and whole milk. The milk will curdle immediately, that's what you want! Stir lightly and cover. Store in the fridge overnight or for a minimum of 5 hours.
Place a coffee filter or cheesecloth into a funnel or sieve and place over your serving pitcher of choice. To make things easier, pour the milky mixture into a large measuring cup with a spout and pour into the coffee filter. The mixture will pass through and come out clear. Add the mixture in increments to not overflow the filter. This process can take 1-2 hours for everything to pass through. Once finished, discard the coffee filter and store the cocktail in the fridge until serving.
To serve, place a large ice cube in a rocks glass and pour the cocktail over it, about two thirds of the way up the glass. Garnish with fresh-grated nutmeg.
