01 -
Get your oven warmed up to 350°F. Grab a 9x13-inch pan and line it with parchment paper, leaving extra on the long edges so you can lift the bars out easily. Spray the bottom lightly with cooking spray so the paper sticks better.
02 -
Mix together 1 cup plus 1 tablespoon flour, 1/4 teaspoon salt, and 1/4 cup sugar in a bowl. Toss in the cold butter cubes and mash with a pastry cutter or your fingers until it looks crumbly. Stir in 1 teaspoon vanilla. Press this evenly into the pan and bake for about 18 to 22 minutes until the edges turn a soft golden color. Let it cool a bit before moving on.
03 -
In a big bowl, whisk 1 cup sugar, 3 tablespoons flour, and 1/2 teaspoon salt. In a separate bowl, beat the 3 eggs. Pour the eggs into the sugar mix and whisk until smooth. Add the fresh lemon juice and the finely grated lemon zest. Carefully stir in the melted butter that’s cooled down a tad until everything’s blended well.
04 -
Put 8 ounces of cranberries, 6 tablespoons sugar, and 1/2 cup water into a small pot. Toss in the optional lemon zest if you like. Cook on medium heat, stirring here and there for 5 to 7 minutes until the berries pop and the sauce thickens like jam. Take it off the heat and gently smash a few berries. Let it cool for a bit.
05 -
Pour the lemon mixture over the baked shortbread crust, spreading it out evenly. Spoon dollops of the cranberry sauce over the lemon layer and swirl gently with a knife or skewer to create a marbled look. Put it back in the oven and bake for 30 to 35 minutes until the lemon part is set but still soft in the middle.
06 -
Let the bars chill completely in the pan on a wire rack. Use the parchment overhang to lift them out. If you want, sprinkle some powdered sugar on top. Cut into bars and enjoy!