This is my second attempt at lemon squares, the first time I tried to make them was pretty much a disaster. I baked the crust and then added the filling as instructed and baked for the time the recipe said. The filling just wouldn't set, so I baked it some more and some more and some more again. After baking it for over twice as long as in the recipe, I figured maybe putting it in the fridge overnight might help. No luck!, as I attempted to cut the slice into squares the next morning the lemon filling oozed all over my bench. It tasted great but it was a mess!
This time I used a Martha Stewart recipe (altered a teensy bit) and they worked out perfectly! Not only tasting great, but looking good. The shortbread base turned out buttery and crumbly and was oh so yummy with the sweet lemon filling.
For the Crust
1 3/4 cups plain flour
12 tablespoons (1 1/2 sticks) butter (frozen)
3/4 cup confectioner's sugar (plus bit extra for dusting)
3/4 teaspoon salt
For the filling
4 large eggs (lightly beaten)
1/4 cup milk
4 tablespoons plain flour (Martha says 3)
1 1/3 cups sugar
3/4 cup freshly squeezed lemon juice (Martha says 3/4)
1 tablespoon lemon zest (not in original recipe)
1/4 teaspoon salt
To make the crust- Preheat oven to 180 degrees c. and grease a 9-by-13-inch baking pan, line with baking paper.
Grate butter with a large hole grater. Whisk together flour, confectioners' sugar, and salt in a large bowl. Add the grated butter and stir with a wooden spoon until combined and mixture looks crumbly. Rub any remaining clumps of butter in with fingertips.
Tip the mixture into the prepared baking pan. Press into an even layer with your hands, leaving a slightly higher lip on the very edges. Place the crust in freezer for 15 minutes. Bake 16 to 18 minutes, until slightly golden. While the base is baking prepare the filling.
To make the filling- Whisk together eggs, sugar, flour, and salt in a large measuring cup or jug until smooth. Stir in lemon juice and milk.To make the slice- remove crust from the oven and immediately pour filling mixture over hot crust. Turn down oven to 160 degrees c, and bake until filling is set and edges are slightly golden brown, about 18 minutes. Allow to cool completely on a wire rack before cutting.
Remove the slice from the pan using the baking paper, dust the top with confectioners' sugar and cut into squares.