1. Preheat oven to 350°F (175°C). Line an 8×8-inch baking pan with parchment paper, leaving overhang on the sides for lifting later.

2. In a bowl, combine 1 cup flour, 1/4 cup sugar, and 1/8 teaspoon salt. Cut in the cold butter until the mixture resembles coarse crumbs.

3. Press the crust mixture firmly into the bottom of the pan and bake for 18–20 minutes, or until lightly golden. Remove and let cool slightly.

4. In a large bowl, whisk together the eggs, 3/4 cup sugar, lemon juice, zest, vanilla, and salt until smooth. Add 1/4 cup flour and whisk until no lumps remain.

5. Fold in the blueberries gently. Pour the filling over the baked crust and spread evenly.

6. Return to oven and bake for 25–30 minutes, until the center is just set.

7. Cool completely, then refrigerate for at least 2 hours before slicing.

8. Dust with powdered sugar before serving if desired.