Sauté potatoes, leeks, celery and garlic with a drizzle of oil or broth until softened and fragrant. About 7-8 minutes.
Add broth, thyme, bay leaf and salt and bring to a rapid boil. About 5-7 minutes.
Once it boils, cover, reduce to a low simmer and cook for about 15 minutes until potatoes are soft and can be pierced with a fork.
Get out the thyme and bay leaf, then carefully put the soup in a blender with the cashews and lemon and blend. It will be hot so be extra cautious.
Add back to the pot if using a blender and stir in the pepper.
Serve with toppings of choice!
Notes
If you are not using a high-speed blender you can either soak the cashews overnight, boil them for 30 minutes or grind them into a fine powder using a coffee grinder.