Ingredients

1 1/2 cups sugar 

3 tablespoons cornstarch 

Salt 

2 cups warm water 

1 stick unsalted butter, cut into small pieces 

1 tablespoon finely grated lemon zest plus 1/2 cup fresh lemon juice (from 2 lemons) 

1/4 cup blood-orange and lime juice (mixed, or one or the other) 

Preparation

Combine sugar, cornstarch, and 1/4 teaspoon salt in a medium saucepan. Whisk in water. Bring to a boil, whisking. Continue to boil, whisking, until clear and thick, about 6 minutes more.

Stir in butter, lemon zest, and citrus juices. Cook, stirring regularly, until smooth, 2 to 3 minutes more.