10-15 grams (about 1/2 an ounce) dried porcini mushrooms
2 tbsp butter or ghee if avoiding all dairy
1 large leek, pale part diced (make sure to rinse the leek well)
1 celery stick, finely diced
3 garlic cloves, diced
10 sprigs of fresh thyme, leaves only (dried can be used as well, about 1 tbsp)
15 medium crimini/Swiss brown mushrooms, roughly diced
1 small sweet potato (use the purple one with white flesh if you can get it), peeled and diced
3 cups good quality chicken or vegetable stock
1 tbsp fish sauce
1/2 tsp Dijon mustard
2 bay leaves
1/2 tsp black pepper
1 tsp lemon zest
1 tbsp lemon juice
3 tbsp cashew, sunflower or almond butter
Garnish: 3-4 button mushrooms, fresh sprigs of thyme, black pepper
1. Place dried porcini mushrooms in a small bowl with boiling water and soak for 15-20 minutes.
2. Once softened, strain but reserve the liquid and dice the mushrooms.
3. While porcini mushrooms are soaking, heat butter or ghee in a large heavy saucepan and sauté diced leek and celery until soft and golden, about 5-7 minutes.
4. Add garlic, thyme, mushrooms and sweet potatoes and stir for a minute until slightly golden as well.
5. Add soaked porcini mushrooms together with about half a cup of reserved mushroom infused liquid. Follow that with the stock, fish sauce, mustard, bay leaf, pepper and lemon zest.
6. Add a little bit more water if the saucepan is overcrowded or if you like your soup on the thinner side. Stir, cover with a lid and bring to boil.
7. Reduce the heat to simmering and cook the soup with the lid on for about 15 minutes.
8. Remove the lid and cook uncovered for a further 5 minutes.
9. Finally transfer to a blender or food processor or use a hand-held puree stick right in the saucepan (off the heat though).
10. Add lemon juice and nut butter and process until well pureed. Taste and season with sea salt if needed, depends on the stock you used.
11. You can also add a little extra lemon juice if you like a bit more zing.
12. If the soup is too thick, you can dilute it with a little warm water.
13. Slice the remaining 5 mushrooms and pan fry them in a little coconut oil or butter until browned and season with a little sea salt.
14. Use those and the fresh thyme sprigs to garnish the soup when served.