Place dried mushrooms in a medium pot with stock and 3 cups of water. Bring to a bubble and reduce heat to simmer.
Heat EVOO, 4 turns of the pan, in a large Dutch oven or soup pot over medium-high heat. Add pancetta and crisp, 2-3 minutes then add mushrooms and bay. Cook 10-12 minutes to soften and darken the mushrooms. Add leeks or onions and garlic, season with salt and pepper, and cook 5 minutes more. Add sage, rosemary and tomatoes.
Remove softened dried mushrooms from the stock and chop. Add them along with their cooking liquids to the soup pot, taking care to leave behind any grit from the mushrooms. Stir in barley and kale, add a little freshly grated nutmeg. Bring soup to a boil, cover and reduce heat to simmer. Cook 20 minutes.