Place the melon balls in a large pitcher, add the honey (2 tablespoons to start), lime juice, and ¼ cup of grappa. Mix gently and let rest in fridge for 1-2 hours or until 1 hour before serving.
Add the moscato wine, mix gently, taste and add more honey or grappa if desired. Keep in mind that you will top it off with sparkling water right before serving, so it’s okay if it’s on the sweeter/stronger side. Refrigerate for another hour.
Right before serving, add ice (or frozen melon balls as ice cubes), lime slices and mint leaves to garnish, and top off with sparkling water. You can prepare the final mix in the pitcher or serve it directly into glasses with melon ice cubes and top off each glass with the sparkling water.