In a cocktail shaker, muddle the mint leaves. Add the lemon juice, simple syrup, vodka, jam and some ice. Put the lid onto the shaker and shake to distribute the jam.
Add some ice to a jam or mason jar and strain in the cocktail. Discard solids in the shaker. Top off with a splash of club soda. If you like a sweeter cocktail, add more jam and stir well. Garnish and serve.
Recipe by In Good Taste at http://ingoodtaste.kitchen/elderberry-mojito/