Vegan Asparagus Soup

I never thought I could make vegan asparagus soup taste this good until I tried this recipe. The combination of fresh asparagus, hearty red lentils, and aromatic tarragon creates a bowl of comfort that satisfies every time. This plant-based soup delivers on both nutrition and flavor, making it an excellent choice for lunch or dinner.

What I love most about this recipe is how the red lentils naturally thicken the soup while adding protein and fiber. The leeks provide a mild onion flavor that complements the asparagus beautifully, and the fresh tarragon gives it an elegant finish that makes this feel like restaurant-quality food made right in your kitchen.

Ingredient Notes

Asparagus: I recommend using fresh asparagus for the best flavor. Look for bright green spears with tight tips. You can use any thickness, but medium spears work well.

Red Lentils: These cook quickly and break down to create a naturally creamy texture. They’re different from green or brown lentils and shouldn’t be substituted.

Leeks: Make sure to clean them thoroughly as dirt can hide between the layers. Use both the white and light green parts, saving the dark green tops for vegetable stock.

Tarragon: Fresh tarragon gives the best flavor, but dried works in a pinch. This herb has a unique anise-like taste that pairs beautifully with asparagus.

Vegetable Broth: Good quality broth makes a difference. I often use half broth and half water to control the sodium content.

Bread Ends: These make excellent homemade croutons. Day-old bread actually works better than fresh for this purpose.

Equipment Needed

• Large soup pot or Dutch oven
• Cutting board and sharp knife
• Measuring cups and spoons
• Immersion blender or regular blender
• Baking sheet (for croutons)
• Fine mesh strainer (optional, for extra smooth texture)

Ingredients

• 1 tablespoon olive oil (or ¼ cup water for oil-free cooking)
• 2 medium leeks, white and light green parts only, sliced
• 1 pound fresh asparagus, trimmed and chopped
• 1 cup dried red lentils, rinsed
• 8-10 fresh tarragon leaves (or ¾ teaspoon dried)
• 5-6 cups vegetable broth or water (or combination)
• Mineral salt and fresh cracked pepper, to taste
• Juice of 1 lemon
• 2 bread ends, cubed
• 1-2 tablespoons garlic-flavored olive oil
• Pinch of garlic powder

How to Make Asparagus Soup from Scratch

1. Heat the olive oil in a large soup pot over medium heat. If using water instead, heat the water until it begins to simmer.
2. Add the sliced leeks and cook for 5-7 minutes, stirring occasionally, until they start to soften and become translucent.
3. Add the chopped asparagus to the pot and cook for another 3-4 minutes, stirring to combine with the leeks.
4. Pour in the red lentils, stirring them into the vegetable mixture. Add the tarragon leaves, crushing them lightly between your fingers as you add them.
5. Add 5 cups of vegetable broth (or your water/broth combination) and bring the mixture to a boil. Reduce heat to medium-low and simmer for 15-20 minutes, until the lentils are completely tender and starting to break down.
6. While the soup simmers, prepare the croutons. Preheat your oven to 400°F (200°C). Toss the cubed bread with garlic-flavored olive oil and a pinch of garlic powder. Spread on a baking sheet and bake for 8-10 minutes until golden and crispy.
7. Once the lentils are tender, remove the pot from heat. Using an immersion blender, puree the soup until smooth. If you prefer a chunkier texture, blend only halfway. If using a regular blender, work in batches and be careful with the hot liquid.
8. If the soup seems too thick, add the remaining cup of broth or water until you reach your desired consistency.
9. Stir in the lemon juice and season with salt and pepper to taste. The lemon brightens all the flavors and balances the earthiness of the lentils.

Tips for Making Roasted Asparagus Soup

• Save the tough asparagus ends for making vegetable stock instead of throwing them away.
• Don’t overcook the asparagus in step 3 – you want to maintain some of the bright green color.
• Taste the soup before adding salt, as vegetable broth can vary in sodium content.
• For extra richness, stir in a tablespoon of tahini or cashew cream before serving.
• If you can’t find fresh tarragon, try fresh dill or parsley as alternatives.
• Make sure your blender or immersion blender is completely clean to avoid any off-flavors.
• The soup will thicken as it cools, so don’t worry if it seems thin when hot.

Serving Suggestions

I like to serve this soup with the homemade garlic croutons on top for added texture and flavor. A drizzle of good olive oil and a sprinkle of fresh herbs make it look restaurant-worthy. The soup pairs well with crusty bread, a simple green salad, or even a grilled cheese sandwich made with your favorite vegan cheese.

For a more filling meal, I sometimes add cooked white beans or chickpeas to make it heartier. A dollop of coconut yogurt or cashew cream can add richness if you want something more indulgent.

How To Store & Reheat

This soup keeps well in the refrigerator for up to 4 days in an airtight container. The lentils will continue to absorb liquid, making the soup thicker over time. When reheating, add a splash of vegetable broth or water to thin it back to your preferred consistency.

You can freeze this soup for up to 3 months. I recommend freezing it without the croutons, which are best made fresh. Thaw overnight in the refrigerator and reheat gently on the stovetop, adding liquid as needed.

To reheat, warm over medium-low heat, stirring occasionally. If using a microwave, heat in 30-second intervals, stirring between each interval to ensure even heating.

Vegan Asparagus Soup FAQs

Can I use frozen asparagus? Yes, but fresh gives better flavor and texture. If using frozen, don’t thaw it first – add it directly to the pot and reduce the cooking time slightly.

What if I don’t have red lentils? Red lentils are key for the creamy texture, but you could substitute with yellow split peas. Green or brown lentils won’t break down the same way.

Is this soup gluten-free? The soup itself is gluten-free, but check your vegetable broth to be sure. Skip the bread croutons or use gluten-free bread instead.

Can I make this oil-free? Absolutely! Use the water sauté method mentioned in the ingredients. The soup will be just as flavorful.

How do I know when the lentils are done? They should be completely soft and many will have broken down into the soup. This usually takes 15-20 minutes of simmering.

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