Place the first four ingredients in a cocktail shaker full of ice. Shake well, until mixture is frothy and drink is chilled. Pour into a martini glass or coupe glass and lightly dust with cinnamon. Garnish with a vanilla bean or maraschino cherry. Serve and enjoy.
Recipe by In Good Taste at http://ingoodtaste.kitchen/spring-brunch-patio-party-recipe-tres-leche-martini/