Serious Eats amaro

1 teaspoon anise seeds
6 fresh sage leaves
6 fresh mint leaves
1 teaspoon fresh rosemary leaves (about 1 sprig's worth)
1 allspice berry
1/2 teaspoon whole cloves
1/2 teaspoon gentian root

3 cups 151-proof neutral grain spirit (see note)
sugar
water

Grind or mortar/pestle everything, put it in the alcohol, steep 3 weeks, shaking frequently.
Add simple syrup and water to taste.
I've tried:
325ml 151-proof alcohol, 125ml syrup, 425ml water. Turned out pretty well, wintery, spicy.
160ml 120-proof alcohol, 100ml syrup, 150ml water. Also turned out well.
210ml 80-proof alcohol, 75ml syrup, 125ml water. A little weak.

Source: Marcia Simmons, Serious Eats, https://www.seriouseats.com/recipes/2012/05/diy-amaro-homemade-amari-averna-recipe.html

Edit: also source: https://www.washingtonpost.com/recipes/amaro-cucciolo/13646/ - theirs has also the rind of 1 grapefruit. That one's from Jeff Faile, tested by Carrie Allan.