Make the syrup: Combine the raspberries, water, and maple syrup in a saucepan.
Bring to a boil over medium heat. Reduce the heat to low and simmer until the
raspberries are softened and juicy, 7 to 10 minutes.
Remove from the heat and stir in the vanilla extract. Allow to cool for at least 10 minutes. Strain the syrup through a fine-mesh sieve set over a small jar or measuring cup.
Make the mocktails by dividing the raspberry syrup, LMNT, and NA spirit between
two 10 to 12-ounce glasses. Stir to mix, then fill with ice and top off with the
sparkling water, divided evenly. For a fun garnish, a strawberry halved and cut into a
heart shape makes it extra special.
