This is a mashup between a traditional Swedish nettle soup and a smooth French-style fish bisque. Any lean, white fish works here. Don't use an oily fish. Or skip the fish and use a potato to thicken the soup. If you don't have nettles, use a 50-50 mix of parsley and spinach for a similar effect. The greenery must be blanched before you use it in this soup. You can buy frozen, cooked spinach, but you'll need to blanch parsley for 1 minute in salty, boiling water before shocking it in an ice bath. Nettles need anywhere from 30 to 90 seconds in the boiling water.
1poundlean white fish or 1 large russet potato, chopped roughly
1poundchopped, blanched nettles,or parsley and spinach
Sour cream and black pepper for garnish
Cook the onions in the butter over medium heat until they are soft and translucent. Add the garlic and cook another minute.
Pour in the stock and add the thyme, nutmeg, salt, fish (or potato) and nettles. Bring this to a gentle simmer and cook for 15-20 minutes. You want the nettles to be very tender.
When the nettles are ready, taste the soup and add salt and nutmeg if it needs it. You want to be able to pick up the nutmeg in the final dish.
Puree the soup in a blender. You might need to do this in batches. If you want to get fancy, push the puree through a fine-meshed strainer. Put back on the stove just to warm through. Serve with a dollop of sour cream and some black pepper.
Don't want to use fish here? Skip it and use 1 large, peeled russet potato instead. Oh, and you don't have to strain the soup after pureeing it. I do because I like refined soups. It'll be fine right out of the blender.