It’s easy to make rosemary syrup from fresh sprigs, and it’s surprisingly affable in cocktail recipes. To keep the bright green color and true flavor intact, we follow a blanching technique as described by Jeffrey Morgenthaler. This one starts with the simple syrup already made, and a few sprigs of rosemary (don’t pick the leaves off just yet). Bring a small pot of water to a boil; separately, prepare a bowl of ice water. Swish the sprigs in the boiling water for 15 seconds, then plunge them in the ice bath for one minute. Dry the leaves, pick them off, and blend them with about a cup of simple syrup (more or less to taste) on high speed for one minute. Strain out the leaves and refrigerate the syrup.
If you prefer a lighter-colored syrup, or don’t want to use a blender, you can make simple syrup, remove from heat, and steep the leaves in the syrup for about 30 minutes. You’ll be missing out on the fresher flavor from the blanching technique, though.
