Vegetarian French Onion Soup With Asparagus & Cheesy Croutons

April 29, 2021
5 Ratings
Photo by Julia Gartland Prop Stylist: Megan Hedgpeth Food Stylist: Sam Seneviratne
  • Prep time 25 minutes
  • Cook time 1 hour
  • Serves 4 to 6
Author Notes

When I think of eating French onion soup, or soupe à l’oignon (gratinée, if topped with bread and cheese, which it nearly always is), I see myself in a tiny Parisian café on a frigid winter afternoon, sipping on a vermouth (Dolin Blanc, one rock, with a twist, thank you so much) in between slurps of the steaming-hot soup. Idyllic as it sounds, that’s not quite the vibe once the weather starts to thaw, and the crisp green vegetables start to replace potatoes and onions for prime spots at the farmers market. (Except for the vermouth part. That’s my drink year-round.) Yet, on spring evenings that slant chilly, there’s still a place in my heart for a warm bowl of soup. Just something a tad fresher. Which brings me to the task at hand: vegetarian French onion soup.

In Mastering the Art of French Cooking, Julia Child’s recipe (a traditional French onion soup if ever there was one) calls for heavy beef stock mixed with caramelized onions, as well as a few tablespoons of flour to thicken the brew. In the interest of budget and simplicity, I forgo stock altogether, relying on even more deeply browned, Maillarded-to-the-max onions (two and a half pounds of them to be exact, about $2.50). When seasoned well and mixed with water, they create their own deeply flavorful, totally vegan stock. For a little flavor help, add a splash of Worcestershire (buy a vegan version or use soy sauce if you’re strictly vegetarian) if you’d like.

Child’s soup is fortified with white wine or dry vermouth, plus a bit of granulated sugar to assist with browning the onions; while I don’t think sugar is truly necessary to brown the onions, it does add flavor, emphasizing onions’ already naturally strong sweetness. Good vermouth—you’ll need about a buck’s worth here—is always cheaper than good wine, and it lasts longer to boot, so that’s a natural addition to this recipe. (Though I don’t call for sugar here, you could use sweet vermouth, blanc or rouge, instead of dry, to channel Child’s sweeter-slanting recipe.)

Onion soup gratinée comes topped with a thick hunk of bread and practically a block of brûléed Gruyère, Swiss, or Comté, which is perfect, but far too wintry for this variation. Instead, we’ll make smaller, crispier croutons from whatever crusty bread you have on hand ($3), covered in a slightly less generous blanket of sharp Cheddar ($1.50).

To fully remind us that spring has sprung, in a wildly nontraditional gesture, just before serving the soup, I stir in fresh asparagus (more affordable when in season, about $2!), which turns the absolute brightest shade of green when it hits the soup. As Child would say, Bon appétit!
Rebecca Firkser

Test Kitchen Notes

Nickel & Dine is a budget column by Rebecca Firkser, assigning editor at Food52 and defender of vermouth. Each month, Rebecca will share an easy, flavor-packed recipe that feeds four (or just you, four times)—all for $10 or less. —The Editors

What You'll Need
Watch This Recipe
Vegetarian French Onion Soup With Asparagus & Cheesy Croutons
  • 4 tablespoons extra-virgin olive oil, divided
  • 2 1/2 pounds onions (red, white, yellow, whatever you have; about 11 small or 8 medium onions), halved lengthwise and thinly sliced
  • Kosher salt
  • Freshly ground black pepper
  • 1/3 cup dry vermouth (or 3 tablespoons white wine vinegar and 2 tablespoons water)
  • 1/2 tablespoon vegan Worcestershire sauce or soy sauce (optional)
  • 1 1/2 ounces shredded (about 1/3 cup) sharp white Cheddar
  • 7 ounces about 3 heaping cups) crusty bread, such as country loaf, miche, or baguette, torn into 1- to 2-inch pieces
  • 10 ounces asparagus, trimmed and cut on the bias into 1-inch pieces
  1. Heat 3 tablespoons of olive oil in a large Dutch oven or stockpot over medium heat. Stir in the onions and season with a couple big pinches of salt and lots of pepper. It will look like way too many onions, but trust me, they’ll cook down. Cook, stirring every 5 or so minutes, until the onions are soft and deeply caramelized, about 40 to 50 minutes depending on your stove. As the onions cook, they’ll start to stick to the bottom of the pot—be sure to gently scrape the bottom of the pot as you stir, or, if there are any really stubborn pieces, add a splash of water to the pot. If you find the onions are looking charred or fried instead of soft and golden, add a splash of water and reduce the heat to medium low.
  2. Stir in the vermouth, let cook for 2 minutes, then stir in the Worcestershire and 8 cups of water. Season with more salt and pepper and turn up the heat to high. Bring the mixture to a boil, then reduce and simmer for 20 minutes. Taste the soup and season with more salt and pepper if needed.
  3. While the soup is simmering, heat the oven to 375°F. Toss the torn bread with the remaining 1 tablespoon olive oil and season lightly with salt and pepper. Bake for 15 to 20 minutes, tossing halfway through, until golden and very crispy. Remove the bread (now toasty croutons) and sprinkle over the cheese. Return the pan to the oven and bake until the cheese melts, about 2 to 3 minutes.
  4. Just before serving, stir in the asparagus to the soup.
  5. Serve the soup topped with cheesy croutons and more black pepper.

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1 Review

Donamaya January 12, 2023
I’ve always used red wine to deglaze the onions , some miso at the end and a small amount of lentils to add that ‘ meaty’ umami in my vegetarian onion aoup