To make the simple syrup: In a small saucepan combine ½ cup sugar and ½ cup water. Bring to a boil, stirring, until sugar has dissolved. Allow to cool.
To make one cocktail: Shake gin, lemon juice, simple syrup and lavender bitters over ice. Strain into a coupe or flute. Top with prosecco & garnish with a lemon twist and/or lavender sprig.