1 cup (230 g) unsalted butter, softened
½ cup (100 g) granulated sugar
2 cups (280 g) all-purpose flour
¼ teaspoon salt
2 cups (400 g) granulated sugar
½ cup (75 g) cornstarch
¼ teaspoon black salt (see notes below)
12 oz (354 ml) evaporated milk
1 cup (240 ml) fresh lemon juice
2 tablespoons lemon zest
1-2 drop yellow food coloring (optional)
Preheat the oven to 350º F/ 180º C. Line the bottom and sides of a 9×13 baking pan with parchment paper (see tip in the notes below), leaving an overhang on the sides to lift the finished bars out. Set aside.
In a medium bowl, cream together with an electric mixer softened butter and sugar. Add flour and salt, mix to blend until the mixture is just combined, about 1 minute.
Place the dough into the prepared pan and press firmly with your fingers into an even layer. TIP: I like to place a piece of parchment paper on top of the dough to help the spreading. NOTE: I highly recommend building up a thin 3/4-inch edge around the sides to keep the filling from spilling beneath the crust and sticking.
Bake for 15-20 minutes or until the edges are very lightly browned. Remove from the oven and set aside.
Reduce oven temperature to 325º F/ 160º C.
Sift the sugar, cornstarch, and salt together in a large bowl.
Add the evaporated milk, lemon juice, lemon zest, and whisk until completely combined. Add 1-2 drops of yellow food coloring if desired.
Pass the mixture through a fine sieve and then pour filling over the crust.
Bake the bars for 20-25 minutes or until the center is relatively set and no longer jiggles. Remove bars from the oven and cool completely at room temperature, for about 2 hours. Then refrigerate for 1-2 more hours until chilled.
Once cool, lift the parchment paper out of the pan using the overhang on the sides. Cut into squares, dust with icing sugar before serving.
NOTE: For neat squares, I recommend using a long serrated knife and wiping the knife clean between each cut.
Cover and store leftover lemon bars in the refrigerator for up to 1 week.