Make simple syrup by adding sugar, lavender and 1 cup water to a small saucepan. Bring to a boil, then simmer about 5 minutes. Pour syrup through a mesh sieve into a measuring cup (or other spouted container), and allow it to cool.
Lavender Lemon Bourbon Sour:
Chill an old-fashioned cocktail glass or a small martini glass. Add lemon juice, syrup, and bourbon to a cocktail shaker with ice, and shake. Strain cocktail out of strainer into the glass. Serve with a lemon slice (optional).