Preheat oven to 350°F (177°C) (see Chef’s Tips).
Lightly grease and line a 9 x 13-inch baking pan with parchment paper, leaving a 2-inch overhang on the longer sides.
In the bowl of a food processor fitted with a metal blade, add in the Redpath® Golden Yellow Sugar and lemon zest. Process until fragrant and thoroughly combined. Add in the flour, cornstarch, and salt. Pulse until well mixed, and no lumps remain. Add in the cubed butter and pulse until it just begins to clump together into a ball.
Evenly press the dough into the prepared pan. Use a flat-bottomed drinking glass or dry measuring cup to smooth out any lumpy areas. Place into the fridge to chill; 10 minutes.
Dock the surface of the chilled dough with a fork. Place into the preheated oven and bake until golden; about 20 to 25 minutes.
While this bakes, make the filling (see Chef’s Tips).
Wipe the food processor bowl and blade used in step 3 above. Washing is not necessary, as the ingredients used are similar.
Place the Redpath® Golden Yellow Sugar, the Redpath® Special Fine Granulated Sugar, lemon zest, and salt into the bowl of the food processor. Process until fragrant and thoroughly combined.
Add the flour and pulse until evenly distributed and no lumps remain.
Transfer the sugar mixture to a large bowl. Add lemon juice and eggs. Gently whisk mixture until smooth and homogeneous (see Chef’s Tips).
When the crust is ready, remove from oven.
Gently stir the lemon filling and pour it over the hot crust. Place the pan back into the oven and bake until the centre is set and no longer jiggles when pan is tapped; 15 to 20 minutes.
Remove the pan from oven and place on a wire cooling rack to cool completely; 1 hour. Place in fridge to chill and firm up before slicing; at least 2 hours.
Remove completely chilled bars from the pan with the help of the parchment paper overhangs. Place on a large cutting board and slice into 24 bars using a large chef’s knife (see Chef’s Tips).
Bars can be garnished with a dusting of Redpath® Icing sugar, edible flowers, or served as is.
*To ensure your oven is at the correct temperature, use an oven thermometer and preheat it for at least 30 minutes before you intend to use it for a more accurate reading. Adjust the oven as needed; for example, if the oven runs hot by 10 degrees, lower the temperature setting by 10 degrees.
*The filling must be poured over the crust while still hot to ensure it adheres.
*If the filling is made before the crust is ready, gently whisk or stir the mixture periodically to prevent the mixture from separating; do not continually mix, as this may aerate the filling too much.
*Dip the chef’s knife into hot water, wiping with a clean kitchen towel, before slicing into the lemon bars. Repeat process with every cut to ensure clean slices.