A - In a bowl whisk the flours together with the yeast. Pour in the water and stir using a spoon. Add the salt and stir to combine. You should obtain a sticky dough, don't try to knead or over-stir. Cover and let it chill for about 30 min, than place in the fridge overnight. The day after your dough will look like the one in the picture: doubled in size and full of  little bubbles.B - Use the spoon to punch down the dough, trying to fold its edges into the center. Place over a tray (spread with oil) and sprinkle some extra virgin olive oil on the top. Cover with a cling film and wait for the second rise.C - Now use your hands to flatten the dough and your fingers to poke the typical holes.D - Bake at 250 degrees for about 15 min, until golden brown.