INGREDIENTS
•
4 large egg yolks
•
1/4 cup sugar
•
3 tablespoons cornstarch
•
3 tablespoons unsweetened cocoa powder
•
1/4 teaspoon salt
•
1 cup milk
•
a 3-ounce bar fine-quality bittersweet chocolate (not unsweetened), broken into pieces
•
2 tablespoons unsalted butter, cut into bits and softened