Stir with ice, strain into chilled cocktail glass.
The vanilla of the Licor 43 takes some of the harsher edges off of the Fiero, rounding out the flavor. I found the two work together in other cocktails as well. I enjoyed the results so much that I picked up another bottle of Fiero.
I built this around Martini & Rossi's Fiero Aperitivo. Fiero is an orange vermouth style, a wine aperitif, with an orange zest/juice dominated profile. I became aware of it while trying to locate "Rossi Aperitif", an ingredient in a few cocktail's from Grassi's 1936 "1000 Misture." This led me to some old advertising posters that featured a big Sun-like orange, with a bottle of the aperitif balanced on its head, looking up with its tongue out, thirsting for a taste.
I can't be certain, but Fiero appears to be a modern version/relaunch of this "Vin Aperitif" as in a 1930's poster by Jean Droit. The 2020 launch of Fiero was aimed at the Aperol spritz market, but there is some parallel to wine based Cappelletti Aperitivo and Fiero seems to have noticeable wormwood as with vermouth.
I decided to combine Fiero with the vanilla notes of Spain's Licor 43, and the sweet resin of Skinos Mastiha to create a bright, sweet, fun orange-vermouth cocktail in the summer holiday vein. Tanqueray London Dry gin was the base spirit.