In a small saucepan, gently heat vodka with the prawn for 5 minutes. Cool and strain to infuse flavor.
In a shaker, combine prawn-infused vodka, dry vermouth, and grated ginger with ice.
Shake until well chilled and strain into a martini glass.
Garnish with a prawn on a cocktail pick and a lemon twist if desired. Serve immediately.
Notes
Infuse vodka with prawn for just a few minutes for best flavor—don't overdo it. Fresh ginger gives punch. Serve extra cold. Try with gin for a different take.