Step 1Heat the oven to 350 degrees. In the bowl of a stand mixer using the paddle attachment, or in a large bowl by hand, mix together the flour, powdered sugar and butter until they come together to form a dough.
Step 2Press the dough into a greased 9-inch-by-13-inch baking dish. Bake the crust until golden-brown, about 20 minutes. Remove and cool. Reduce the oven temperature to 300 degrees to bake the bars.
Step 1In a large bowl, whisk together the eggs, sugar, lemon juice and flour. Pour the filling into the prepared crust.
Step 2Place the dish in the center of the oven and bake at 300 degrees until the custard is set, about 40 minutes. Cool to room temperature, then dust with a light coating of powdered sugar before serving.