Place the dried morels in a large bowl. Bring the seven cups of chicken broth to a boil and pour over the morels. Set aside to rehydrate for about 20 minutes. Use a slotted spoon to remove the mushrooms, reserving the broth.
Coarsely chop the morels.
Heat the butter in a large pot over medium to medium high heat. Add the trumpet royale mushrooms and rehydrated mushrooms and cook, stirring from time to time, until the mushrooms are soft and somewhat dry. This should require about six minutes.
Add the leek and the shallot and continue cooking, covered, stirring from time to time.
When the shallot becomes translucent (about four minutes), add the flour, blending and stirring constantly, and cook for about two minutes more. Add the reserved mushroom broth, taking care to remove any grit or dirt that may have settled to the bottom. Bring to a boil while whisking constantly.
Tie the parsley, thyme, and bay leaf together with a piece of string and add to the soup in a bundle. Lower the heat and simmer for about ten minutes.
Remove from the heat and allow to cool. Remove the herb bundle.
In batches, transfer the mixture to a blender and puree until smooth.
Use a sieve to strain the mushroom puree. Return the puree to the pot and reheat over medium heat.
Whisk the heavy cream and Madeira into the soup. Season with salt and pepper to taste.
Serve in preheated soup bowls.