Taken from the Abel & Cole newsletter, reproduced here for ease of looking-up. Serves 4–6. NB I think this is a vast underestimate of the amount of liquid you need. I only used 300g of bread (home-made sourdough spelt, home-made rye/barley) and had to more than double the liquid.
Melt the butter in a large frying pan over medium heat; add the onion and celeriac and cook until soft (about 15 minutes), stirring occasionally. Add thyme, salt, and parsley.
Put the bread in a large bowl and pour the stock over; add the vegetables and mix well. Spoon into a greased baking dish and bake uncovered at 180C/356F/Gas 4 until browned.
Photo by Bob, GIMPed/mogrified by
me.