Chocolate & Vanilla Pudding

This is from America's Test Kitchen.
I will never buy "instant" pudding boxes again... This recipe is just as fast, and I actually know all the ingredients that I am eating without added preservatives. It's very rich, so you don't need to eat a large serving of it.

Vanilla Pudding:

3/4 c. sugar

2 T. cornstarch

1/4 t. salt

3 1/2 c. half-and-half

3 large egg yolks

1 T. unsalted butter

1 T. vanilla extract

Combine sugar, cornstarch, and salt in a medium saucepan. Slowly whisk in the half-and-half and then the yolks.

Bring the mixture to a simmer over medium-high heat, whisking gently but constantly and scraping the bottom and sides of the pot. Reduce the heat to medium and cook, stirring constantly, until the pudding is thick and coast the back of a spoon, 1 to 2 minutes.

Strain the pudding through a fine-mesh strainer into a bowl, scraping the inside of the strainer with a rubber spatula to pass the pudding through. Stir the butter and vanilla into the pudding until the butter is melted. Press plastic wrap directly on the surface to prevent a skin from forming and refrigerate until set, about 3 hours.

For Double-Chocolate Pudding:

Reduce the cornstarch to 4 teaspoons. Add 2 tablespoons cocoa powder with the cornstarch in the first step. Add 6 oz. melted semisweet or bittersweet chocolate to the mixture following the yolks in the first step and reduce the vanilla to 2 teaspoons. (The chocolate may form clumps, but they will smooth out during cooking).