Combine 1 cup granulated sugar and 1 cup water in a small saucepan over medium heat. Cook, stirring very frequently, until sugar is dissolved and mixture is hot. (Do not boil.)
While simple syrup cooks, place 4 large sprigs rosemary on a cutting board. Hit with a kitchen mallet a few times to gently bruise the rosemary. (If you don't have a mallet, use a rolling pin, or smack between hands.)
When simple syrup is done cooking, remove from heat. Add rosemary, pressing down to cover in syrup. Set mixture aside for 20 to 30 minutes, allowing rosemary flavor to infuse syrup. (Taste after 20 minutes. Then proceed to next step, or continue steeping rosemary for stronger flavor.)
Place fine mesh strainer over a bowl or large measuring cup. Strain syrup, then let cool before using.
Prepare Lemonade:
Add 1 cup lemon juice, plus all of the rosemary syrup to a large pitcher. Mix well.
Stir in 5 cups cold water.
Serve lemonade over ice, or refrigerate until ready to drink. Enjoy!
Notes
I recommend making the rosemary syrup a couple hours or a day in advance, then chilling it. That way, you're not standing around waiting for it to cool.Make sure to read the info before this recipe card for helpful tips, recipe variations, related recipes, and more!