LEMON BAR

This is a delicious yet really simple recipe from a friend in Washington. I normally adapt recipes that people share with me after I test them a few times - but this time I give it to you exactly as I received it: firstly, because in addition to being a great cook, she is a brilliant writer and I would not dare to touch a single coma of something written by a Pulitzer prize; and secondly because I have (finally!) found somebody who is as curt with cooking instructions as I am. This is it:

"Blend together 2 cups of flour, half a cup of sugar and one cup of softened butter (I do it in the food processor) 
Pat into the bottom of a 9 x 11 pan to make the crust.
Bake at 350° for 20 minutes.
While it’s baking, zest and juice two lemons. Whisk together with four eggs, half a cup sugar, quarter of a cup flour. 
Pour over baked crust and bake again for 20 to 25 minutes (The bars firm up as they cool – – if I want a really stiff bar I use the longer baking time.  Shorter time just makes a gooier bar) they keep really well"

Tips for the non-American:
2 cups of flour: 240 g
half a cup of sugar: 100 g
cup of butter: 115 g
350 F: 180 C