Place a large bowl on the scale and zero it out. Measure out the starter, water, salt, olive oil and stir to combine.
Add the flour and then mix vigorously with a spoon to make sure all the ingredients are combined. At this point I will also feed my starter with equal amounts water and flour and allow it to sit out overnight as well.
In the morning the dough will have more than doubled in size and the starter will be bubbly. Put the starter back in the fridge until next time you want to make bread.
Preheat the oven to 400 F. Oil the bottom of the quarter sheet tray.
Place a sheet of parchment paper on top of the oiled tray. Then drizzle more oil on top of the paper and spread it with your hands to coat the entire surface.
Using your oily hands, remove the dough from the bowl into the prepared tray.
Spread the dough using your hands (it really helps if they have oil on them so the dough doesn't stick) so that it fills the entire tray and cover with a damp dish towel to allow the dough to rise again for 20 minutes.
After 20 minutes, remove the towel and oil the surface of the dough. Then press your finger tips into the dough to create the dimples that are traditional to focaccia.
Sprinkle with flaky salt. You can stop here and bake it off but we like dollops of marinara sauce on ours. You could also sprinkle some chopped rosemary or thin slices of onion or tomato. Sky's the limit. Just don't skip the flaky salt.
Bake on the middle rake at 400 F for 45 minutes. Then remove to a cooling rack.
Slice as you desire and enjoy!
