Heat 2 cups beef broth until boiling and pour over the dried mushrooms. Let the mushrooms soak until they are rehydrated and plump, about 10 minutes. If the mushrooms float, place a small bowl or plate on top of them to keep them submerged.
Finely chop about a pound of assorted mushrooms and sprinkle with the juice of one lemon. Or, chop them in a food processor and sprinkle with lemon juice. These mushrooms will be small bits floating in the soup liquid to thicken and flavor the soup.
Put 2 T butter in a medium-large dutch oven, melt over medium heat and saute' the garlic, 2 T shallots, and 1 pound of finely chopped mushrooms, until they are just cooked and the mushrooms start to release their liquid. Stir regularly so nothing sticks or burns.
While the mushrooms, shallots, and garlic are cooking, take out the rehydrated mushrooms, and finely chop the caps. Discard the stems and any caps that are not soft. Add the finely chopped rehydrated mushrooms to the dutch oven and saute' briefly with the other mushrooms and the shallots.
After the shallots and mushrooms are cooked, add the following to the Dutch oven: 1 1/2 cups of the beef broth used to rehydrate the mushrooms, 1 can beef consomme', 1 cup heavy whipping cream, 1 cup water, 1 bay leaf, 1 - 2 sprigs of thyme, and squeeze in any remaining lemon juice.
Bring to a boil, then reduce heat and simmer about 20 minutes.
While the soup is simmering, cook the bacon, then use a little bacon grease to saute' the 3 cups roughly chopped assorted mushrooms. These larger pieces will give you something to "bite into" and provide a nice contrast with the creamy base. Add the sauteed mushrooms to the soup.
Mix 3 T water and 1 T cornstarch, stir until the cornstarch is dissolved. Then, when the soup IS NOT boiling, add the cornstarch slurry to the soup. Stir continuously and increase the heat to bring the soup to a boil. The cornstarch will thicken the soup, and the amount of thickening happens right after it boils. If you want a thicker soup, make a second slurry of cornstarch and water, and add it incrementally. Stir continuously and bring to a boil after each addition.
Garnish with bacon and chopped scallions.