1-First Step: Preparation and mise en place Before you begin baking, it’s essential to have all your ingredients measured and ready. Start by preheating your oven to 350°F (175°C). For the crust, you’ll need 2 cups of all-purpose flour, ½ cup of powdered sugar, and 1 cup of softened unsalted butter. For the filling, gather 4 large eggs, 2 cups of granulated sugar, ¼ cup of flour, ½ cup of fresh lemon juice (about 3 lemons), and 1 tablespoon of lemon zest. Prepare a 9×13-inch baking pan by greasing it thoroughly with butter or cooking spray. For easier removal, you can also line the pan with parchment paper, leaving some overhang to use as handles when lifting the bars out later. If you’re not using fresh lemons, now is the time to do so. Zest the lemons before juicing them to get the most flavor from the peel. Measure out all your ingredients precisely, as baking requires accuracy for consistent results.

2-Second Step: Making the crust In a medium bowl, combine 2 cups of all-purpose flour and ½ cup of powdered sugar. Add a pinch of salt to enhance the flavors. Cut in 1 cup of softened butter using a pastry blender or two forks until the mixture resembles coarse crumbs. Alternatively, you can use a stand mixer with the paddle attachment to combine the ingredients until they form a crumbly mixture. The mixture should hold together when pressed but remain crumbly in texture. This creates the shortbread-like crust that will provide a sturdy base for your lemon filling.

3-Third Step: Baking the crust Press the crumbly mixture firmly and evenly into the bottom of your prepared 9×13-inch pan. Using the back of a measuring cup or your hands, ensure the crust is evenly distributed and compacted. This step is crucial as it prevents the filling from seeping underneath the crust during baking. Place the pan in the preheated oven and bake for 15-18 minutes, or until the crust is lightly golden around the edges. While the crust is baking, you can prepare the lemon filling, which you’ll pour over the hot crust.

4-Fourth Step: Preparing the filling In a large bowl, whisk together 4 large eggs and 2 cups of granulated sugar until well combined. The mixture will become slightly lighter in color as you whisk. Add ¼ cup of all-purpose flour and whisk until smooth. Stir in ½ cup of fresh lemon juice and 1 tablespoon of lemon zest. If you prefer a brighter yellow color for your filling, add a few drops of yellow food coloring at this stage. Whisk the mixture until all ingredients are thoroughly incorporated. The filling should be smooth and free of lumps. The flour helps stabilize the eggs and sugar, creating a texture that sets beautifully while remaining slightly soft and custard-like.

5-Fifth Step: Adding the filling to the crust Once the crust is lightly golden, remove it from the oven but keep the oven on. Immediately pour the lemon filling over the hot crust. This immediate transfer is important as it helps create a seal between the crust and filling, preventing the filling from making the crust soggy. Gently tap the pan on the counter a few times to release any air bubbles in the filling. Return the pan to the oven and bake for an additional 20-25 minutes, or until the filling is set but still slightly jiggly in the center, similar to a pumpkin pie. The edges should be firm, but the center may still have a slight wobble. This residual heat will continue to cook the filling as it cools, resulting in the perfect consistency.

6-Sixth Step: Cooling, chilling, and serving Allow the bars to cool completely in the pan on a wire rack, which will take about 1-2 hours. Once cooled, refrigerate the pan for at least 2 hours or overnight to allow the filling to set completely. This chilling step is essential for achieving clean cuts when slicing. When ready to serve, lift the bars out of the pan using the parchment paper handles (if used) or cut directly in the pan. Use a sharp knife to cut into squares, wiping the knife clean between cuts for neat edges. Dust the tops generously with powdered sugar just before serving for a beautiful finishing touch. The contrast between the bright yellow filling and the white sugar creates an attractive presentation that’s perfect for gatherings.