Preheat your oven to 325°F (163°C). Prepare a 9x13-inch glass baking pan by lining the bottom and sides with parchment paper, ensuring an overhang on the sides for easy removal. This will make cutting the bars easier. Set aside.
For the crust, in a medium bowl, combine the melted butter, sugar, vanilla extract, and salt. Add the all-purpose flour and stir until the mixture forms a thick dough.
Press this dough firmly into the prepared pan to create an even crust layer. Bake in the preheated oven for 20-22 minutes or until the edges are lightly browned.
Remove the crust from the oven and, while it’s still warm, use a fork to poke holes all over the top, making sure not to pierce through the crust entirely. This step will help the filling adhere and secure the crust in place. Set aside for now.
To make the filling, sift the granulated sugar and flour into a large mixing bowl. Whisk in the eggs and then the freshly squeezed lemon juice until the mixture is thoroughly combined.
Pour the lemon filling over the warm crust, ensuring it spreads evenly. Bake the bars for 22-26 minutes, or until the centre is set and no longer jiggles when gently tapped.
Remove the lemon bars from the oven and allow them to cool completely at room temperature. This usually takes about 2 hours. You can then refrigerate them for an additional 1-2 hours for a delightful chilled result, though it’s optional.
Once the bars are cool, use the parchment paper overhang to lift them out of the pan. Dust the top with confectioners’ sugar for an extra touch of sweetness. Cut into squares for serving, ensuring a clean knife for neat cuts.