The Ultimate Lemon Butter Bar

The Ultimate Lemon Butter Bar

yield: Makes 1 1/2 dozen 2 2/3-inch by 1 1/3-inch bars

This classic cookie combines two of my favorite sweets: buttery-tender Scottish shortbread and satiny lilting English lemon curd. The problem has always been getting a firm enough topping and avoiding a soggy shortbread base. The special technique discovered for this recipe virtually guarantees success.

The clean, refreshing flavor of lemon makes these the perfect sweets to follow a rich Christmas goose.

Ingredients

Shortbread Base

• 10 tablespoons unsalted butter (cold) (5 ounces = 142 grams)
• 2 tablespoons powdered sugar (0.5 ounce = 14 grams)
• 2 tablespoons granulated sugar (0.75 ounce = 25 grams)
• 1 1/4 cups bleached all-purpose flour (dip and sweep method) (6.25 ounces = 180 grams)

Lemon Curd Topping

• 4 large egg yolks (2 full fluid ounces = 2.5 ounces = 74 grams)
• 3/4 cup sugar (5.25 ounces = 150 grams)
• 3 fluid ounces (use a liquid measuring cup) lemon juice, freshly squeezed (about 2 1/2 large lemons) (3.25 ounces = 94 grams)
• 4 tablespoons unsalted butter (softened) (2 ounces = 57 grams)
• Pinch of salt
• 2 teaspoons lemon zest (finely grated) (4 grams)
• 2 tablespoons powdered sugar for dusting (0.5 ounce = 14 grams)

Repartion

EQUIPMENT:
8-inch by 8-inch by 2-inch baking pan, preferably metal (if using a glass pan, lower the oven temperature 25°F.), bottom and 2 sides lined with an 8-inch by 16-inch strip of heavy-duty aluminum foil.

Food Processor Method
Cut the butter into 1-inch cubes, wrap it, and refrigerate.

In a food processor with the metal blade, process the sugars for 1 minute or so, until the sugar is very fine. Add the butter and pulse in until the sugar disappears. Add the flour and pulse in until there are a lot of little moist crumbly pieces and no dry flour particles remain.

Dump the mixture into a plastic bag and press it together. Remove the dough from the plastic bag and knead it lightly, until it holds together.

Electric Mixer Method or by Hand
In Scotland, it is said that the best shortbread is mixed with the fingers and that each woman's fingers lend something distinctive and special to the finished cookie. I find that the texture is more delicate when the dough is mixed with the fingers rather than in a machine. For either method, use superfine sugar for the best texture and be sure to soften the butter.

In a medium bowl, whisk together the sugars. In a large bowl, cream the butter with the sugars until light and fluffy. With your fingers or with the electric mixer, mix in the flour until incorporated. If using the mixer, add the flour in 2 parts.

The Ultimate Lemon Butter Bar