It's as easy as pie to make bars from smooth, tangylemon filling and fluffy meringue atop a buttery zest-flecked crust.
Preheat oven to 350. Make crust: Put butter, flour, confectioners sugar, 2 teaspoons lemon zest, and the salt in the bowl of an electric mixer fitted withthe paddle attachment. Mix on mediumspeed until well blended.
Transfer mixture to a 9-by-13-inch rimmed baking sheet. Press batter evenly into baking sheet. Chill in freezer 10 minutes. Bake until golden, 20 to 22 minutes. Let cool completely on a wire rack.
Make filling: Whisk together whole eggs, 1 3/4 cups plus 2 tablespoons granulated sugar, the lemon juice, and 1 tablespoon plus 2 teaspoons lemon zest. Pour over crust. Bake until filling is set, 18 to20 minutes. Let cool completely on a wirerack. Keep oven at 350.
Make meringue topping: Put egg whites and 1/2 cup granulated sugar in the clean bowl of an electric mixer fitted with the whisk attachment. Beat on medium-high speed until stiff peaks form.
Using an offset spatula or the back of a spoon, spread meringue over filling, swirling to create soft peaks. Bake until meringue begins to brown, 8 to 10 minutes. Let cool completely. Cut into bars. Bars can be refrigerated in an airtight container, up to 1 day.