Instructions

• Preheat the oven to 350°F. Line a 13x9x2" baking pan with parchment paper so the paper comes most of the way up the sides (leave an overhang on two opposite sides to lift the bars out later). Set a wire rack nearby.
• Make the crust: in the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer), beat 1/2 lb (16 Tbsp) room-temperature unsalted butter and 1/2 cup granulated sugar until light and combined. Add 1 1/2 tsp vanilla extract, then add 2 cups all-purpose flour and 1/4 tsp salt. Mix on low-medium speed until the mixture is crumbly and no dry flour remains.
• Press the crust mixture evenly into the bottom of the prepared pan using your fingertips or the bottom of a flat measuring cup to create a uniform layer. Bake the crust in the preheated 350°F oven for 18–20 minutes, or until the edges are lightly golden. Remove the pan to the wire rack and let the crust cool slightly while you make the filling. Keep the oven on.
• Prepare lemons: zest lemons first to measure 2 Tbsp lemon zest, then squeeze fresh lemons to measure 1 cup lemon juice (recipe note: this will be about 5 large or 8 medium lemons). Set zest and juice aside.
• Make the filling: in a large mixing bowl, whisk together 7 large room-temperature eggs and 3 cups granulated sugar until the mixture is blended and slightly smooth. Whisk in the 1 cup fresh lemon juice and the 2 Tbsp lemon zest until combined. Add 1 cup all-purpose flour and whisk until the filling is smooth and no visible traces of flour remain.
• Pour the filling over the warm crust, spreading gently if needed to an even layer. Return the pan to the center of the preheated 350°F oven and bake for 30–35 minutes, or until the filling is set — the center should no longer be wobbly (a slight, very gentle jiggle is fine, but it should not look liquid).
• Remove the pan from the oven and cool on the wire rack at room temperature for at least 1 hour. After the initial cooling, refrigerate the pan for at least 2 hours to fully set the filling.
• To serve: use the parchment overhang to lift the chilled lemon bars from the pan and transfer them to a cutting board. Cut into 18–20 squares (wipe the knife between cuts for cleaner edges if desired). Dust the tops with confectioners sugar before serving.