Nettle, Leek and Potato Soup with Garlic-Brown Butter Croutons

Spring is here, and one of the first areas of the garden to poke up green leaves is the stinging nettle patch. If you can avoid the sting, the nettle is one of the healthiest, most delicious perennials that’s super-easy to propagate — and is the superstar of this soup, made with leeks, potatoes, and the green, green nettle. 

There’s no getting around the fact that the stinging nettle is the unloved weed, the lurking Triffid, the snarling Caliban, if you will, of the British landscape. If you thought otherwise, let me show you the plant in its natural habitat:

But despite its rather unprepossessing appearance, its urban ubiquity, and the unpleasant electric-shock feeling of walking into one, nettles are one of the most nutritious and tasty spring greens you can cook with. Last spring we made a nettle risotto with garlic and taleggio, and this year we’re combining nettles with leeks and potatoes to create a rich, green soup, sprinkled with brown butter – garlic croutons and wild violets from the garden. 

If you buy nettle seeds, as we did, from Hudson Valley Seed Company, you’ll see the following on the product page:  “All northerners feel a special fondness for the wild greens of early spring”. That poetic declaration might be written over the garden gate of every gardener in zones 6 and below, because it strikes deep and true.  Whether the winter that’s just passed has been long and hard, or long and cold, or long and miserable, it has inevitably been long. While other regions are enjoying daffodils in late February and planting annuals in March, Northerners wait for the magical weekend in late April or even early May when the last risk of frost passes and we won’t be consigning our hopeful tomato starters to a grim, frozen fate. 

So the first signs of green — from any quarter — brighten our seasonally-depressed hearts like a sunbeam shining down from the firmament. The vegetable patch demands even greater patience. True, your garlic will have been sprouting up even since early January, but it won’t be ready for harvest till June.  Rhubarb plants will crown over the soil (or the snow) earlier in the year, but their stalks won’t be substantial enough to cook for a few weeks yet. In our garden, the first perennial to be fully ready to eat is the stinging nettle.

Along with the nettles, the blossoming peach trees and redbuds, and the grass which I realize with a shock that I will soon have to mow, the yard has also filled up over the last couple of weeks with the purple and white underlay of wild violets. These bright tiny flowers are easy to overlook but are perfectly edible. (We’ll be making something special with them in an upcoming post.) We decided to pair these wild foraged beauties in the presentation of the nettle soup, and we’re so happy we did.

This is the perfect time to harvest nettles: while they’re still young and tender, and before they develop tougher leaves, thick stems and seeds. And really, if it weren’t for the stings, you could treat them exactly like spinach or kale. But stinging is kind of their thing, and so you will need to pick them with thick gloves, before giving them a quick blanch in boiling, salted water followed by a dip in an ice bath (to ensure the leaves remain green). As soon as they hit the boiling water they no longer sting, so you can ditch the gloves after that point. Squeeze the blanched nettles to get out most of the excess liquid and if you haven’t already done so, discard any thick, fibrous stems and give the leaves a rough chop.

(Note: you can also use fresh or frozen spinach in place of the nettles.)

Once the nettles are blanched, making the rest of the soup is a snap. I usually blanch the nettles in my favorite soup pot (which is a Le Creuset Dutch Oven), then I pour out the water, give it a quick rinse and use it again for the soup. Cook the leeks, along with a pinch of kosher salt, in butter or olive oil until they’re soft and translucent. If you don’t have leeks, an onion would be just fine. Add the garlic and cook until it smells delicious, which takes less than a minute.

Pour in the stock (or use water), and add in the peeled, chopped-up potatoes along with the bay leaves and thyme. Bring it to a boil, lower the heat and let it simmer until the potatoes are fully cooked through. You should be able to easily piece them through with a paring knife. Depending on how large your potato chunks are, this will take 10 to 15 minutes. 

(Note: Use a starchy potato, like russets or Yukon Gold. Waxy potatoes (like the red skinned variety) won’t break down and thicken the soup as well.)

Once the potatoes are cooked, add the nettles back in and let them simmer for a few minutes, mostly to heat them back up. Remove the bay leaves and purée the soup using either an immersion blender or (working in batches) a counter-top blender. If you used the countertop blender, add the soup back to the pot, and stir in the lemon juice and the crème fraîche (sour cream makes a fine alternative, though if you don’t do dairy, just leave it out). 

If you’re making the brown butter & garlic croutons, make them while the potatoes are cooking. I like to tear up pieces of good country style bread — the irregular shape makes them extra crispy. For four bowls of nettle soup, about 1 1/2 cups of torn bread pieces (a little less than one slice, per bowl) is plenty. 

Tips on making brown butter — whether you’re making brown butter for croutons, pasta sauce or anything else, the method is the same. Use a light-colored 8-inch pan (stainless steel is perfect here because it’s hard to see the color of the butter in a dark non-stick or cast iron). Make sure the pan has a relatively thick bottom (meeeow) so the butter doesn’t scorch. Turn the heat to low and melt the butter slowly while swirling the pan. Once the butter is melted, you can turn the heat up a little, to medium. The water in the butter will start to sizzle and spit, but keep gently swirling the pan and scraping the bottom with a silicone spatula (this keeps the milk solids from settling to the bottom and burning).

Once the butter turns light golden brown and smells nutty and delicious, it’s time to add in the garlic. Let the garlic sizzle for a few seconds, then add in the bread and toss it in the garlic butter, then cook the bread pieces, tossing them often, until they turn golden brown and turn crisp. Tip them onto a plate, season them with salt and pepper to taste, and try not to nibble them down to nothing before the nettle soup is ready. 

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5 from 2 votes

Nettle, Leek and Potato Soup with Garlic-Brown Butter Croutons

If you can avoid its sting, the nettle is one of the healthiest, most delicious perennials that's super-easy to propagate — and is the superstar of this soup, made with leeks, potatoes, and the green, green nettle. 

Prep Time30 minutes mins

Cook Time45 minutes mins

Total Time1 hour hr 15 minutes mins

Course: Entree, Soup

Cuisine: british

Servings: 6

Calories: 213kcal

Author: Emily Clifton, Nerds with Knives

Ingredients

• 10 oz young nettles (4 packed cups), thick stems removed (or substitute fresh spinach or 1 box of frozen spinach)
• Kosher salt
• 2 tablespoons unsalted butter or olive oil
• 2 large leeks white and light green parts only, washed and sliced
• 3 cloves garlic minced
• 1 pound Yukon Gold or russet potatoes peeled and cut into 2 inch chunks
• 5 cups chicken or vegetable stock low sodium
• 2 bay leaves
• 2 teaspoons fresh thyme leaves
• Freshly ground black pepper
• 2 tablespoons lemon juice
• 3 tablespoons crème fraîche plus more for drizzling

For the Garlic-Brown Butter Croutons

• 2 tablespoons unsalted butter
• 1 large clove garlic minced
• 1 1/2 cups country bread torn into 1-inch craggy pieces
• Kosher salt and pepper to taste
• Violets for garnish (optional)

Instructions

For the soup

• Bring five quarts of salted water to a boil in a large pot. Prepare another large bowl with ice water. Using gloves, strip the leaves from the picked nettles and discard any stalks or seeds (although you want to pick before seed stage: see note in article). Give the leaves a rinse to remove any dirt and then add leaves to the boiling water. Blanch until fully wilted, about 1 to 2 minutes. Using tongs or a slotted spoon, remove the leaves and transfer them immediately into the ice water. Stir them gently (you can use your hands at this stage) until cool, then drain in a colander. Roughly chop the cooled nettles and set them aside.
• Melt the butter in a 6 quart soup pot set over medium heat. Add the leeks and a pinch of salt, and cook, stirring often, until soft but not brown, about 5 minutes. Add the garlic and cook for 1 minute. Stir in the potatoes, stock, bay leaves, and thyme. Turn the heat up to high and bring the liquid to a boil, then lower the heat and simmer until the potatoes are fully cooked through, easily pierced with a paring knife, about 15 minutes. Add the blanched nettles and simmer everything together for another 5 minutes.
• Turn off the heat and remove and discard the bay leaves. Purée the soup either using an immersion blender or, working in batches, a standing blender (return the soup to the pot). If the soup is too thick, add water to thin it to the desired consistency. Stir in the lemon juice and crème fraîche and season the soup to taste with salt and pepper.

For the Garlic-Brown Butter Croutons

• Heat a medium (8-inch) skillet over low heat. Add the butter and swirl until melted, then raise the heat to medium and cook , swirling often, until the butter turns light golden brown and smells nutty, about 2 to 3 minutes. Add the garlic and cook until fragrant, about 30 seconds. Stir in the bread pieces, toss in the garlic butter until coated and keep cooking and tossing until the bread browns and crisps in spots, about 3 to 4 minutes. Transfer to a bowl and season with salt and pepper, to taste.
• Serve the soup hot, with a swirl of crème fraîche and some garlic croutons on top. Decorate with a few fresh violets, if using.

Nutrition

Calories: 213kcal | Carbohydrates: 25g | Protein: 8g | Fat: 10g | Saturated Fat: 6g | Trans Fat: 1g | Cholesterol: 23mg | Sodium: 77mg | Potassium: 728mg | Fiber: 5g | Sugar: 2g | Vitamin A: 1797IU | Vitamin C: 13mg | Calcium: 281mg | Iron: 3mg

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