In batches, cook the mushrooms. It will take time to brown all of them, but you want the mushrooms to sweat, the liquid to evaporate, and the mushrooms to brown. Cook, stirring regularly, for about 10 minutes.
Once most of the liquid has evaporated, transfer the cooked mushrooms to the bowl of the vegetables and bacon and brown the remaining mushrooms, adding more bacon fat if needed.
During the last minute of the last batch of mushrooms cooking, turn the heat to high and add all the vegetables, remaining mushrooms, and bacon back to the pot.
Add 1 cup of the chicken stock and scrape up any browned bits stuck to the bottom of the pot. Next, add the remaining chicken stock, the porcini mushrooms, and the mushroom-soaking liquid. Finally, add the bundle of thyme and rosemary. Bring to a boil and then reduce heat and simmer for 30 minutes.