The Mazatlan (Tequila Manhattan)

½ oz Paula’s Texas Orange
1½ oz añejo tequila
1 oz sweet vermouth
a dash Angostura bitters
an orange peel for garnish

Stir with ice (don’t shake) and serve up or in an old fashion glass. Optionally garnish with an orange twist.

Source
http://pts.nwalsh.com/recipes/martinistyle/mazatlan.html