Begin by making lemon-ginger simple syrup. In a small saucepan, combine lemon juice, sugar, water, and 2 large slices of fresh ginger + 4 lavender sprigs. Simmer gently over low heat, stirring occasionally, until sugar has completely dissolved.
Continue to simmer for another 2 minutes. set mixture aside to cool. Discard simmered ginger.
To serve, fill glasses with ice. add 2 parts lemon-ginger syrup to one part seltzer + a touch of Belvedere Ginger Zest Vodka, if desired.