Stir, strain into old fashioned glass with a large cube or sphere or a Nick & Nora glass. Garnish with an expressed lemon swath.
Fernet Branca is a bit of a bully in this drink, so if Letherbee Fernet isn't available, I'd recommend either another, slightly less intense fernet or a split of say Branca and Nardini. The Bitter Truth Allspice Dram is drier with a stronger allspice taste than the St. Elizabeth, if using the former, try maybe .5 oz and .25 oz demerara syrup.
Part of my ongoing "4 parts, equal parts, stirred" series.