If you are preparing a fancy ice cube for your cocktail, fill a silicone ice cube mold of your choosing with filtered water. Freeze overnight.
In a small saucepan, combine all ingredients for the lemon simple syrup over medium heat. Bring mixture to a rolling boil. Then, turn down the heat and let simmer for about 10 minutes, stirring occasionally. Strain into a jar and let cool.
Place an ice cube in a clean glass. Add ¾ oz lemon simple syrup, a few raspberries, and top off with Gem + Jane Yuzu Raspberry Rose. Stir mixture using a barspoon. Optional: garnish with fresh mint