Place the strawberries in a bowl and fold in with vodka and mint. Store in the refrigerator until cold about 1 hour.
In a small saucepan over low heat, mix water and sugar until dissolved. Add lemongrass, ginger and lemon zest and bring to a simmer. Cover with a plate or lid and reduce by 1/2, or until a syrupy consistency is achieved, about 45 minutes.
Mix in lemon juice and keep syrup warm on low heat. Bloom the gelatin in 1 cup water and add to warm syrup to dissolve. Strain syrup and keep at room temperature. It will thicken as it cools.
Place syrup in a foaming canister with 2 cartridges and set aside. Strain the strawberries before serving and place the strained vodka in the freezer (optional).
In 4 chilled martini glasses, place a small mound of the strawberries. Foam the lemongrass mixture on top and garnish with mint sprig.
Beverage suggestion: Chilled Fino Sherry, Bandol Rose Domaine Tempier 1998