Preheat the oven to 350°F (175°C) and prepare a 9x13-inch baking pan.

Combine 1 cup flour, 1/2 cup granulated sugar, and 1/2 cup melted butter in a mixing bowl. Press into the bottom of the prepared pan and bake for 15-20 minutes until golden.

Allow the crust to cool for about 10 minutes.

In a large bowl, whisk together 1 cup lemon juice, zest of two lemons, 1 cup granulated sugar, 2 beaten eggs, and 1/4 cup flour until smooth.

Blend 1 cup raspberries until smooth and strain through a sieve. Fold half of the lemon mixture into the raspberry puree.

Pour the lemon filling over the cooled crust. Drop raspberry mixture over the lemon filling and swirl together without over-mixing.

Bake for 25-30 minutes until set but slightly jiggly in the center. Let cool for 30 minutes, then refrigerate for at least 2 hours.

Remove from the pan using parchment edges, dust with powdered sugar, cut into squares, and serve chilled.