Heat oven to 325 degrees. In a medium bowl, combine 1 1/2 cups flour and confectioners' sugar. Using a pastry cutter, cut in butter until mixture resembles coarse meal. Gently pat into a 9-by-13-inch glass baking dish, and bake until crust is golden brown, 20 to 25 minutes. Transfer dish to a rack to cool.
Reduce oven to 300 degrees. Whisk together eggs and granulated sugar in a medium bowl. Add lemon zest and juice, and combine. Sift in remaining 1/2 cup flour, add nuts, and stir to combine. Pour filling onto baked crust, and bake until filling sets, about 40 minutes. Refrigerate until well chilled before slicing, 1 hour and preferably overnight. Dust with confectioners' sugar, slice into pieces with a sharp knife, and serve.
If you're fond of limes, use fresh lime juice and zest instead.