1. In a saucepan over medium heat, combine cranberries, sugar, and water. Cook until the berries burst and the mixture thickens. Stir in cornstarch and simmer 1–2 more minutes. Strain through a sieve for a smooth puree. Set aside to cool completely.

2. Preheat oven to 350°F (175°C). Line a 9×13 inch baking pan with parchment paper.

3. In a mixing bowl, combine butter, flour, sugar, and salt for the crust. Mix until crumbly. Press into the bottom of the pan.

4. Bake the crust for 18–20 minutes until lightly golden. Remove from oven.

5. In a clean bowl, whisk together eggs, sugar, flour, lemon juice, and lemon zest until smooth. Pour over the warm crust.

6. Drop spoonfuls of the cooled cranberry mixture on top. Use a skewer or knife to gently swirl for a marbled look.

7. Return the pan to the oven and bake for 22–25 minutes until the center is just set.

8. Let cool to room temperature in the pan, then refrigerate for at least 1 hour.

9. Lift out using parchment, slice into squares, and dust with powdered sugar before serving.