Prepare the Glass: Place 6 fresh raspberries and a generous amount of fresh mint leaves into your highball glass.
Muddle the Ingredients: Using a muddler, gently press down and twist on the raspberries and mint leaves to release their juices and essential oils. Be careful not to shred the mint leaves completely, just bruise them to release flavor.
Add Concentrate and Ice: Measure and pour 2 oz of the homemade Raspberry Lemonade Concentrate over the muddled raspberry and mint. Fill the glass with ice cubes, leaving some room at the top for the sparkling water.
Add Sparkling Water: Slowly top off the glass with sparkling water, leaving about an inch from the rim. This will preserve the carbonation and prevent it from overflowing.
Garnish and Serve: Stir the mixture gently with a bar spoon to combine the flavors without losing the fizz. Slice a small wedge from the lemon, make a slit in the center and place it on the rim of the glass for garnish.