This topic is bittersweet, because while the Manhattan may be the most perfect cocktail ever made, it's highly overdone, and even its myriad variations can begin to lose their edge.
Luckily, I have an old recipe that I (ostensibly) created on a whim a few years back and occasionally whip up when the mood strikes me.
The taste of Manhattans for me always invokes cold weather; on the other hand, the taste of tequila for me always invokes summer. This drink tries to bridge the gap, perhaps perfect for those last days of summer when the first chilly breezes blow away what's left of the heat.
I went heavy on the Angostura to bring out a bit more of the black pepper from the anejo.
I suppose you could technically call this an equal-parts tequila Manhattan, heavy on the bitters. Instead I'll call it...
1.5 oz anejo tequila
1.5 oz sweet vermouth
6-8 dashes Angostura bitters
Stir with ice and strain into a cocktail glass. No garnish.