Lemon Custard Filling

Ingredients

• 0.5 cups white sugar
• 0.25 cups cornstarch
• 0.25 teaspoons salt
• 0.75 cups water
• 2 large egg yolks
• 0.33 cups lemon juice
• 2 tablespoons unsalted butter

Instructions

1. 1

   Combine sugar, cornstarch, and salt in the top of a double boiler over simmering water. Stir frequently, scraping down the sides with a rubber spatula to avoid scorching, until sugar is melted, 3 to 5 minutes.

2. 2

   Whisk water and egg yolks together in a small bowl; pour into sugar the mixture, whisking until fully incorporated. Cook, stirring constantly, until the mixture thickens, 3 to 5 minutes.

3. 3

   Remove from the heat and stir in lemon juice and butter until incorporated. Cover with plastic wrap and let sit until completely cooled.