
Creato con AI
In a medium saucepan, combine the granulated sugar and cornstarch.
Gradually stir in the water until the mixture is smooth.
Cook over medium heat, stirring constantly, until the mixture thickens and begins to boil.
Boil for 1 minute, continuing to stir.
Remove the saucepan from the heat and stir in the lemon zest, lemon juice, and unsalted butter.
Mix until the butter is completely melted and the mixture is smooth.
Allow the lemon filling to cool before using it to fill doughnuts.