Combine strawberry puree, sugar, lemon juice, and corn syrup in a saucepan. Heat over medium, stirring until sugar dissolves.
Sprinkle gelatin over the mixture, whisk until fully dissolved. Cook until just beginning to simmer, then remove from heat.
If using, stir in citric acid.
Quickly pour the mixture into silicone molds or a lightly greased pan.
Chill in the refrigerator for 1-2 hours until firm.
Pop gummies out of molds or cut into shapes if using a pan. Toss in granulated sugar if desired.