Ingredients:

• 1 large egg yolk
• 1 tablespoon plus 1/2 teaspoon sugar
• 1 1/2 teaspoons all-purpose flour
• 1/3 cup whole milk
• 6 tablespoons chilled heavy cream
• 1 1/2 oz fine-quality bittersweet chocolate (not unsweetened)
• 1 to 2 teaspoons dark rum
• 1/4 teaspoon instant-espresso powder (optional

Instructions:

1. Vigorously whisk together yolk, 1 tablespoon sugar, flour, and a pinch of salt until well blended. Heat milk and 3 tablespoons cream in a small heavy saucepan until hot but not boiling. Add about one third of hot milk to yolk mixture in a slow stream, whisking constantly. Add remaining milk, whisking, then transfer to saucepan. Bring to a simmer, whisking constantly, then continue to simmer, still whisking constantly, until thickened, about 1 minute.
2. Remove from heat and add chocolate, rum (to taste), and espresso powder if using. Let stand until chocolate is melted, about 30 seconds, then whisk until smooth. Transfer to a glass and chill, covered, at least 30 minutes to cool quickly to room temperature.
3. Just before serving, vigorously whisk remaining 3 tablespoons cream with remaining 1/2 teaspoon sugar in a small bowl until it holds soft peaks. Top pudding with whipped cream.

Cooks’ note: Pudding can be made 1 day ahead and chilled, covered. Bring to room temperature before serving.