oniony flatbread

I made caramelized onions a couple of days ago. Five-and-a-half pounds of sliced raw onions filled my seven liter pan right to the top:



After cooking for four hours, they'd shrunk down to a little more than a pint:



I'm not sure what all I'm going to do with them; I may put some in a potato gratin, and they'll probably be a good soup ingredient. The first thing I tried was using them as a flatbread topping, and they did this very well.



Oniony Spelt Flatbread

Sponge:
200g whole spelt flour
350ml water
1/8t instant yeast

dough:
the sponge
300g bread flour
1/2t instant yeast
10g salt, about 1 1/2t
50ml olive oil

toppings:
olive oil
a handful of caramelized onions
a handful of oil-cured olives, pitted and halved
a couple of sprigs of thyme, stemmed

The night before you bake, whisk together the sponge ingredients and let rest, covered, at room temp.

In the morning, add the flour and yeast to the sponge, mix till it's a shaggy mass, and let rest 20 minutes. Add the remaining dough ingredients and mix thoroughly. Briefly knead the dough every 20 minutes for an hour, then let rise till it's tripled and you're ready to shape it.

Heat the oven with a baking stone in it to 450ºF. Stretch the dough out on a piece of parchment paper till it's a big rectangle, about 10"x14". Cover with a tea towel and let rest for half an hour.

Dimple the dough with your fingers, drizzle olive oil over it, then artfully scatter the rest of the toppings.



Slide onto the baking stone, and bake about 15 minutes. You may have to turn it around partway through so that it bakes evenly.