Preheat the oven to 325°F (163°C). Line the bottom and sides of a 9×13 glass or ceramic baking dish* with parchment paper, leaving an overhang on the sides to lift the finished bars out. (This makes cutting easier!). Set aside.
Mix the melted butter, sugar, vanilla extract, and salt together in a medium bowl. Add the flour and stir to completely combine. (The dough will be thick.) Press firmly into prepared pan, making sure the layer of crust is nice and even. Pop it into the fridge for about 15 minutes to chill slightly.
Bake for 20-22 minutes or until the edges are lightly browned. Remove from the oven. Using a fork, poke holes all over just the the top layer of the warm crust (NOT all the way through the crust.) This really does help the filling stick and holds the crust in place. Set aside to cool just slightly.
Sift the sugar and flour together in a large bowl. Add the eggs and fresh lemon juice and whisk until completely combined.
Pour filling over the warm crust. Bake the bars for 20-22 minutes or until the center is relatively set and no longer jiggles. (Give the pan a light tap with an oven mitt to test.) Remove bars from the oven and cool completely at room temperature. Cool them about 1 1/2 hours at room temp then pop in the fridge for another hour or 2 until cold.
Once cool, lift the parchment paper out of the pan using the overhang on the sides. Dust with confectioners’ sugar and cut into squares before serving. (For neat squares, wipe the knife clean between each cut.) Cover and store leftover lemon bars in the refrigerator for up to 1 week. Serve chilled.
Freezing Instructions: Lemon bars can be frozen for up to 3-4 months. Cut the cooled bars (without confectioners’ sugar topping) into squares, then place onto a baking sheet. Freeze for 1 hour. Individually wrap each bar in aluminum foil or parchment and plastic wrap and place into a large bag or freezer container to freeze. Thaw in the refrigerator, then dust with confectioners’ sugar before serving.
*A glass or ceramic dish is recommended over metal for superior taste. (A metal dish tends to impart a metallic flavor.)
*Fresh lemon juice should be used. (Or another fresh citrus like orange, lime or blood orange.)
*Docking, or using a fork to poke holes at the top of the baked crust is a great idea to ensure the filling sticks to the crust. Just be sure not to poke the holes all the way through or you'll end up with filling under your crust.