2 oz of Tequila
1 oz of dark creme de cacao (or chocolate liqueur)
1 oz of heavy cream
1/4 tsp of unsweetened cocoa powder (or tang powdered soft drink)
Pour tequila, dark creme de cacao and cream into a cocktail shaker half-filled with ice cubes. Shake and strain into a cocktail glass. Garnish with cocoa powder dusted over the top, and serve.