Lemon Pastry Cream Recipe

In a large bowl, set up an ice bath by partially filling it with a combination of cold water and ice. Set aside. In a medium heatproof mixing bowl set on top of a dampened towel (this serves as a stable base), stir together sugar, cornstarch, and salt. Whisk in egg yolks until mixture is pale yellow, smooth, and fluffy, about 1 minute. In a 2-quart stainless steel saucier, combine milk and lemon zest. Bring to a bare simmer over medium heat. Remove milk from heat. While whisking continuously, slowly pour milk into egg yolk mixture in a thin stream until all of it has been added. Return the mixture to the same saucier. Cook over medium heat, whisking constantly until pastry cream begins to thicken, about 2 minutes. Once it thickens, continue to whisk, pausing every few seconds to check for bubbles, about 1 minute. When it begins to bubble, set a timer and continue whisking for 1 minute. This step is important to neutralize starch-dissolving protein found in egg yolks. Off-heat, whisk in butter until melted and thoroughly combined. Strain pastry cream through a fine-mesh strainer set over a medium heatproof bowl. Immediately place plastic wrap or buttered parchment paper directly on the surface of the cream to prevent a skin from forming. Transfer bowl to prepared ice bath to chill for 30 minutes, then refrigerate until cold, about 2 hours. When you are ready to use the pastry cream, add lemon juice and whisk until smooth.