Genepy liqueur is made from mountain herbs. It backs up the herbaceous - and unabashedly bitter - Suze. Different brands vary in strength so add whatever amount (as indicated) works best for your taste.

If you can't get or find Genepy liqueur, you can use another herbal spirit, like Chartreuse (I prefer green, but yellow will work - use the larger amount if using the yellow as it's milder) or Izarra, or leave it out. In the U.S., Forthave Spirits makes Yellow genepy spirit. It's a great cocktail with or without it!