Spinach Ciabatta

Directions

1. 1
   In a blender, puree the spinach and water until smooth. If you want to juice the spinach, you can do that too, then just stir the warm water in after.
2. 2
   In the bowl of an electric mixer, mix the flour, salt, and yeast to combine, 15 seconds. Add the spinach/water mixture and mix on low speed for 3 minutes. Scrape the bowl well to ensure all the flour has been fully incorporated. Raise speed to medium and mix for 2 minutes more.
3. 3
   Transfer the dough (it will be very thin - don't panic!) to a large greased bowl. Cover with plastic wrap and let rise until double in size, about 1 hour.
4. 4
   Line two baking sheets with parchment paper. Use a sifter to generously dust your work surface with flour (at least 14 x 14 inches). The layer of flour should be thin - not built up too high, but you it should be coated enough that you shouldn't be able to see the work surface underneath the flour. Turn the dough out onto the floured surface, then generously flour the surface of the dough as well.
5. 5
   Use a bench knife to cut the dough in half. With one of the prepared baking sheets nearby, carefully pick up the loaf and gently transfer it to the baking sheet - the dough will stretch a bit and elongate the shape when you lift it, that's ok!
6. 6
   Repeat with the other loaf and the second baking sheet. Cover each loaf with plastic and let rise until noticeably puffy, 35-45 minutes. Towards the end of rise time, preheat the oven to 450°F with two racks positioned near the lower end of the oven. Have ready a 9x13 inch pan and 2 cups of ice cubes.
7. 7
   Remove the plastic from the loaves and transfer to the oven. Place the 9x13 inch pan with ice cubes on the base of the oven. Close the oven door and bake for 15-20 minutes. Switch the loaves on the racks and continue to bake until very crisp, 8-10 minutes more. Let cool completely before slicing and serving.