Take half of the morels and half of the porcinis and grind in a clean coffee grinder into a fine powder. Take half of this mixture and along with salt and pepper, coat the entire roast and set aside. Take the remaining mushroom powder and place in a saucepan with the cream and bring to a simmer and remove from heat. Take the other half of the mushrooms and place in a bowl and cover with boiling water and let sit ten minutes, remove and chop roughly, saving one cup of the liquid. In a saucepan sweat the garlic and shallot in the butter. While the wine is reducing, sear the Chateaubriand on all sides and place in a hot (400 degree) for twenty minutes or until a thermometer inserted into the thickest part reads 155 degrees. Add the white wine to the shallots and reduce until almost dry and reduce. Add the beef stock and reduce by half. Add one cup of the mushroom liquid and reduce by half. Add the cream to this mixture and reduce by half. Season the sauce with salt and pepper to taste and strain through a fine meshed sieve and add reconstituted mushrooms. Remove the roast from the oven and let rest for ten to fifteen minutes. Slice and serve with the mushroom cream sauce.