How to Make It
Prepare the crust: Preheat oven to 350°F. Line an 8-inch square baking pan with aluminum foil, leaving several inches extending over sides for handles. Coat foil with cooking spray.
Whisk together flour, sugar, and salt in a medium bowl. Melt butter in a skillet over medium heat until butter foams, begins to brown, and smells nutty, 2 to 3 minutes. Remove from heat; cool 10 minutes. Slowly add browned butter to flour mixture; stirring with a fork until combined. Press mixture into bottom of prepared pan. Bake until puffed and very light golden, 20 to 25 minutes. Remove from oven.
Prepare the filling: Whisk together eggs, yolk, flour, salt, and 1 cup of the sugar in a large bowl. Add zest and juice; whisk until combined. Pour into hot baked crust. Bake until just set, 13 to 15 minutes. Remove from oven and heat broiler to high. Top lemon bars with remaining 1 tablespoon sugar and broil until top becomes golden in spots, 1 to 2 minutes. (Alternatively, brown the top with a kitchen torch.)
Cool completely in pan, about 1 hour. Remove from pan using foil sides as handles; cut into 16 squares.