The best lemon bars

Ingredients:

Cake

• 1 and 3/4 cups premium flour
• 1/4 cup cornstarch
• 1/4 cup powdered sugar
• 0.5 tsp coarse salt
• 220 g chilled unsalted butter, cut into small pieces

Filling

• 4 large eggs
• 2 large egg yolks
• 1 and 3/4 cups sugar
• 1/3 cup premium flour
• 1/4 teaspoon coarse salt
• 1 cup freshly squeezed lemon juice (6-8 lemons)
• 1 teaspoon finely grated lemon zest
• 110 g chilled unsalted butter, cut into small pieces
• 1 tbsp powdered sugar, for dusting

Preparation:

1. Preheat oven to 350°F (175°C). Line a 9 x 13-inch baking sheet with foil, leaving an overhang on both sides; lightly spray with cooking spray. Set aside.
2. Cake:
   
   In the bowl of a food processor, combine the flour, cornstarch, powdered sugar, and salt and pulse 10 times to combine. Add the chilled butter and pulse until the mixture resembles coarse sand, about 30 times. The dough will not come together. Pour the mixture evenly into the prepared pan and press it down lightly. Bake, rotating the pan halfway through, until the edges are golden brown, 20 to 25 minutes.
3. Filling:
   
   In a medium saucepan, combine the eggs, yolks, sugar, flour, salt, and lemon juice. Heat over medium heat, whisking constantly, scraping the sides of the pan occasionally with a rubber spatula, until the cream thickens, 4-5 minutes. Remove from heat and stir in the lemon zest and butter until completely melted.
4. Reduce oven temperature to 150°C. Spread the filling on the crust and bake until completely set, 12-15 minutes.
5. Place on a wire rack to cool to room temperature, then refrigerate until the filling is completely set, about 2 hours.
6. Pull the foil overhangs to lift the dessert out of the pan. Remove the foil and cut into squares. Dust with powdered sugar just before serving.