So, for the bottom layer of the dough add the softened butter, the sugar, beat into a soft mousse to whitening, then add flour...

... and make dough. Take the form (I 13х22), will setelem baking paper, gently turn the dough out and send the form into the fridge for 30 minutes. In the meantime warm up the oven to 180 degrees.

After 30 minutes take out the form with the dough and bake it in the oven for 30 minutes to light it will turn brown. I slightly overexposed... well, it's no big deal, but it is better not to overdo, the basis will be more tender))

While baked basis, we will make the top layer cakes. To do this properly will beat into a soft mousse eggs with jam, and then mix with the flour. A little more about the flour: classic lemon squares top layer should be soft, something like a pudding, baked custard... I did layer more denser, somewhere between pudding and soft dough. So, in fact, the amount of flour and jam approximate, can vary depending on Your preference)

So, take out the base from oven, allow to cool 10 minutes, pour on top of lemon layer and again in the oven for 15-20 minutes. When ready, take out and fully cooled before serving. Best served straight from the fridge, sprinkled with powdered sugar.