Soak lentils in water for 4 hours. Drain and rinse.
Rinse mixed dried mushrooms and add to bowl with 4 cups of hot water for 10 minutes to rehydrate.
Heat olive oil over medium heat in large pot. Add onions, garlic and chopped fresh mushrooms. Cook until mushrooms release their juices, about 10 minutes.
Remove rehydrated mushrooms from water and chop roughly.
Add lentils, rehydrated mushrooms, water from mushrooms, vegetable stock, tamari, salt and pepper to the pot of cooked mushrooms, onions and garlic. Bring to boil, then reduce heat and simmer for 20-25 minutes, until lentils are tender.
Stir in cashew cream and fresh thyme. Let soup simmer from five minutes to heat cashew cream