1Combine first 3 ingredients in a medium saucepan. Gradually add milk, stirring with a wire whisk until smooth. Cook over medium-low heat, stirring constantly, 25 to 30 minutes or until mixture is thickened. Remove from heat; stir in liqueur and vanilla.
2Spoon mixture into individual dessert dishes. Cover and chill thoroughly. Just before serving, sprinkle evenly with crushed peppermint.