Soak porcinis in 1 c warm water for 30 minutes, strain and reserve the liquid Heat the oil and butter until foaming, then add onion, shallots and garlic and saute for about 5 minutes (until softened) Add fresh mushrooms to the pan and stir until softened.
Add stock and bring to a boil.
Add the porcinis, liquid, thyme and salt and pepper.
Lower the heat and simmer for 30 minutes, stirring occasionally.
Process 3/4 of the soup in a blender (immersion blender is perfect).
Add cream and heat through.
Correct seasonings if necessary and garnish with fresh thyme and cracked black pepper.