Mix dough ingredients, reserving 50g of water, to a mixing bowl and mix with a scraper. 2-5 mins. Slowly add in the 50g of the reserved water if the dough feels like it can handle it- I left over only a little. You don't want it soupy!
*note: One day I forgot to reserve some water -used it all and bread was fabulous!!
Let it sit 30 mins and do a stretch & fold. Repeat this for a total of 4-5 stretch & folds covering in between. (I used a proofing box so did not cover.) Do this every 30 mins.
Transfer to oiled cambro let bulk fermentation finish.
Lightly flour your work surface and scrape out your dough.
Pull sides up into a boule and rest 20 mins uncovered.
Shape the dough into a rectangle and add inclusions of onions and cheeses at this point. Shape into a boule or batard then place the dough in bannetons with rice flour on the bottom.
At this point I put mine in fridge overnight and baked in the morning.
Score the loaf and bake at 450 covered 20 mins. (I used a pizza stone and baking shell.)
Remove cover, place a pan under the rack and bake uncovered -took 35-40 more mins and I tented with foil to avoid over browning.
Cool at least an hour!