Meanwhile, in 2-quart saucepan, mix 3/4 cup sugar, the cornstarch and salt with whisk. Beat in milk, followed by eggs, using whisk. Heat over medium heat to boiling until thickened, stirring constantly, 10 to 12 minutes. Press mixture through strainer to remove any lumps; stir in butter and 1 teaspoon vanilla. Refrigerate until completely cooled, 30 to 45 minutes.