In 2-quart saucepan, beat 3/4 cup granulated sugar, the cornstarch, water and lemon juice with whisk. In small bowl, mash 1 1/2 cups sliced strawberries with fork to make 1 cup mashed strawberries; stir into pan. Cook over medium heat, stirring constantly until mixture thickens and boils. Boil and stir one minute. Pour into medium bowl; cool 5 minutes.