Place tequila, agave syrup and bitters in a cocktail mixing glass with ice cubes.
Stir gently for at least 30 seconds.
Strain into another glass filled with a large ice cube and garnish with an orange peel, if desired.
Añejo tequila is a must in this recipe. It's an aged spirit that was made for sipping rather than mixing with other liqueurs. Yes, it's pricier than your average silver or reposado tequila that you might have on hand for margaritas, but it makes a huge difference in the flavor and smoothness of this drink.
Don't have agave syrup? You can substitute simple syrup but you may need to increase the amount as agave is sweeter than a traditional 1:1 simple syrup.
Use a large ice cube for this drink. A large sphere or cube melts and dilutes the drink slowly. This ensures your cocktail is the perfect temperature and consistency from the first sip to the last. You can buy them at the liquor store or make your own at home using a silicone mold.
Stirring for the full 30 seconds is important. It helps to uniformly distribute the agave syrup evenly as well as evenly chill the drink. Don't just do a quick spin; your drink will taste unbalanced.