In a large bowl, stir together the strawberries, lemon zest, and lemon juice. Set aside.

In a large saucepan over medium heat, whisk together the sugar, cornstarch, and water until smooth and combined. Bring to a boil and boil for 1 minute.

Add the strawberries, gently stir in and simmer for 2-3 minutes.

Remove saucepan from the heat and gently stir in the Jell-O powder, careful to not crush the strawberries.

Let the mixture cool at room temperature for 2 hours, then refrigerate until fully chilled and settled. Transfer to a sealed container and refrigerate for 5 days.

Use on pies or other desserts.