Chocolate Guinness Pudding

In a large nonreactive mixing bowl, whisk together egg yolks and sugar. Set aside.

Open the can of Guinness and slowly pour it into a 4-cup measuring cup, pouring down the side of the cup to reduce foaming. Pour half of the Guinness (about 7/8 cup) into a heavy-bottomed 3-quart saucepan (set the rest aside). Add 2 1/4 cups cream and whisk to combine. Set over medium heat and heat, whisking occasionally, until bubbles just begin to form at the edges. Remove from heat, add chocolate, and whisk until smooth.

Slowly pour the hot chocolate mixture into the egg and sugar mixture, whisking constantly to prevent curdling. Return mixture to saucepan and set over moderately low heat. Cook, whisking constantly, until mixture thickens and coats the back of a spoon, about 15 minutes. (Pudding will look separated.) Pour into a blender and blend on high for 1 minute. Divide pudding among the glasses, leaving at least 1 inch of space at the top of each. Cover with plastic wrap and refrigerate until chilled and set.

Meanwhile, pour the remaining Guinness into a small saucepan and bring to boil over medium heat. Reduce heat to moderately low and simmer, uncovered, until reduced to 1 tablespoon, about 20 minutes. Pour syrup into a small bowl and let cool.

Beat remaining cream in a small bowl until soft peaks form. Add the Guinness syrup and beat until combined. Divide cream among the 6 glasses of pudding and serve.