Ingredients
2 cups whole milk
1/2 cup sugar
1/2 vanilla bean, split lengthwise, seeds scraped and reserved
Pinch of salt
4 large egg yolks
1/4 cup cornstarch
2 tablespoons unsalted butter, cut into 1/2-inch pieces
Preparation
Bring milk, 1/4 cup sugar, vanilla bean and seeds, and salt to a simmer in a medium saucepan over medium heat.
Whisk egg yolks, cornstarch, and remaining 1/4 cup sugar in a medium bowl. Whisking, slowly pour about 1/2 cup of hot milk mixture into yolk mixture. Slowly add remaining milk mixture until incorporated. Pour mixture back into the saucepan, and cook over medium-high heat, whisking, until it begins to bubble in center and registers 160 degrees on an instant-read thermometer, about 2 minutes. Remove from heat; discard vanilla bean.
Transfer to the bowl of an electric mixer fitted with the paddle attachment. Add butter; beat on medium speed until butter has melted and mixture has cooled, about 5 minutes. Cover with plastic wrap, pressing it directly onto surface to prevent a skin from forming. Refrigerate until cold, at least 2 hours or up to 2 days. Just before using, beat on low speed or whisk by hand until smooth.
