Asparagus and green garlic soup. Photo: Kate Williams

The best part about spring cooking is working with so many different shades of green. All of the produce showing up at the farmers market paints a verdant picture filled with artichokes, asparagus, spinach, scallions, leeks and herbs. A bright green bowl of asparagus soup, chilled to retain its vibrancy, is the perfect way to capture the season.

Getting that color to stick around, however, requires a little more work than just sautéing and blending a pile of vegetables. Asparagus quickly turns muddy brown if left to cook too long or spritzed with too much lemon juice. It must be quickly cooked and chilled to keep both its flavor and color. Furthermore, asparagus tends to be stringy and fibrous — the enemies of any blender that isn’t of the Vitamix persuasion. (I don’t have a Vitamix.)

The further I delved into asparagus soup making, the more and more my chef-y instincts came out. Why blanch asparagus in water when you can use a flavorful vegetable stock? Why buy vegetable stock when you’re creating vegetable scraps while you trim and chop your ingredients? Why struggle to get the soup smooth if you can remove the fibrous asparagus skins ahead of time? Why add cream when you can complement the flavor of the green vegetables with grassy (and green) olive oil?

What follows is what I’ve found to be the best way to get a truly smooth, truly asparagus-y asparagus soup. I use the woody asparagus ends, plus vegetable trimmings, to make a quick vegetable stock that I use to blanch and simmer the veggies and, later, to thin the soup. To bolster the asparagus, I’ve used a combination of yellow onion and fresh green garlic. For thickening the soup, I simmered a small potato in that vegetable stock, and, for sautéing, I used olive oil — which makes the recipe both vegan and gluten-free.

And, yes, I’m asking you to peel asparagus. I know, it’s a huge pain. However, unless you can find enough ultra-tender, thin spears to make this soup, you’ll likely end up with a soup full of fibrous strings. Peeling the spears eliminates those bits and, by putting the skins in the vegetable stock, you’ll still get all of their flavor in the final soup.

For the ultra-ist ultra-smooth soup, you’ll still need to strain the soup before blending it with olive oil (another cool trick to add creamy texture), but you definitely don’t have to do so. If you’re tired of cooking by that point, just move the soup to the fridge and serve it when you’re ready.

Asparagus and green garlic soup. Photo: Kate Williams

Asparagus and Green Garlic Soup

Note: This recipe seems long, but much of the prep work has been integrated into the recipe in order to make it easy to build a flavorful vegetable stock. That said, if you’d like to streamline the recipe a bit, here’s what you can cut: Purchase small, tender asparagus and skip the peeling step; however, you’ll likely need to strain the soup. Alternatively, take the time to peel the asparagus and then skip the straining step. If you’ve got a high-powered blender, such as a Vitamix, you can get an ultra-smooth result without straining. (Lucky you!) And if you do choose to make the recipe as written (and recommended), you can make it up to a day ahead of time and serve it straight from the fridge.

Serves 4 to 6

2 pounds asparagus
1 small onion, halved
2 stalks green garlic or 1 small clove garlic, thinly sliced
1 4-ounce yukon gold potato
Kosher salt and freshly ground black pepper
1/4 cup plus 1 tablespoon extra-virgin olive oil
Zest of 1 lemon

Trim off the woody ends from the asparagus and place in a large saucepan. Use a sharp vegetable peeler to peel the skins off of the remaining asparagus stalks. Place the peels in the saucepan and set the asparagus aside.

Place one half of the onion in the saucepan. Peel the other half, placing the peel in the saucepan. Finely dice the onion, placing the root end of the onion in the saucepan. Set the diced onion aside.

Peel the potato, placing the peel in the saucepan. Cut the potato into 1/4-inch dice and set aside.

Slice off the dark green ends from the green garlic and place in the saucepan. Thinly slice the light green and white parts of the green garlic and set aside. Place the root end in the saucepan. (If using garlic cloves, skip this step.)

Homemade vegetable stock. Photo: Kate Williams

Add 8 cups water and 1 teaspoon salt to the saucepan, place it over high heat, and bring to a boil. Reduce the heat to low and simmer until the stock is flavorful, about 20 minutes. Strain the stock through a fine mesh strainer set over a large bowl. Wash out the saucepan and then pour the strained stock back into the pan.

Meanwhile, slice off the asparagus tips and set aside. Chop the remaining asparagus stalks into rough 1/2- to 1-inch pieces.

Bring the strained stock back to a boil over high heat. Prepare an ice bath in a large bowl. Set a medium bowl inside the ice bath.

Add the asparagus tips to the boiling stock and cook just until they turn bright green, about 30 seconds. Use a slotted spoon to transfer the tips to the bowl in the ice bath.

Blanching asparagus tips in broth. Photo: Kate WIlliams

Add the asparagus stalks to the boiling stock and cook just until they turn bright green, about 1 minute. Use a slotted spoon to transfer the stalks to the bowl with the tips. Let both cool completely. They should still be green and crisp-tender.

Remove the bowl from the ice bath and pick out the prettiest 12 or so tips. Slice in half lengthwise (if desired) and set aside for serving.

Add more ice to the ice bath (if needed) and place the saucepan with the stock directly into the ice water. Let the stock cool to room temperature.

Meanwhile, heat 1 tablespoon of the olive oil in a medium skillet over medium heat. Add the diced onion and a generous pinch of salt and cook, stirring frequently, until the onion is tender but not yet browned, 3 to 5 minutes. If the onion is browning too quickly, reduce the heat to medium-low.

Add the sliced green garlic and continue to cook until tender, about 2 minutes. Add the diced potato and give the mixture a stir. Pour in about 1 cup of the stock, reduce the heat to medium low and simmer until the potatoes are tender, 7 to 10 minutes. Transfer the mixture to a bowl and let cool to room temperature.

Blending the soup. Photo: Kate Williams

Once everything has cooled, transfer the asparagus stalks and cooked onion-green garlic-potato mixture to a blender. (If you have a small blender, you may need to blend in two batches.) Add 3 cups of the stock and blend until very smooth, 1 to 2 minutes.

If you’d like, you can strain the mixture to get it silky smooth: Place a fine mesh strainer over a large bowl and pour the soup through the strainer. Use a firm rubber spatula to press the solids through the strainer. Use a clean spatula to scrape off any solids that stick to the bottom of the strainer. You should be able to get most of the solids through the strainer. Rinse out the blender jar and add enough soup to fill the blender up no more than three-quarters of the way full. (Keep the rest of the soup in the large bowl.)

Alternatively, you can skip this step and keep the soup in the blender.

With the blender running, drizzle in the remaining 1/4 cup olive oil. Blend in the lemon zest and season to taste with salt and pepper. Pour the soup back into the large bowl and stir to combine. Refrigerate until very cold, at least 1 hour.

Serve the soup garnished with the asparagus tips, a generous drizzle of olive oil, and freshly ground pepper.

Kate Williams has been writing about food since 2009. After spending two years developing recipes for cookbooks at America’s Test Kitchen, she moved to Berkeley and began work as a freelance writer and...