This Spring Vegetable Soup is a bright, nourishing bowl that celebrates the best of the season. Tender asparagus, sweet green peas, zucchini, baby carrots, and wilted spinach simmer together in a savory vegetable broth, finished with a squeeze of fresh lemon juice that ties every flavor together beautifully. It comes together in under 45 minutes, is naturally vegetarian and easily vegan, and makes incredible leftovers that taste even better the next day.
Dice the onion, mince the garlic, peel and slice the carrots into thin rounds, thinly slice the celery, dice the zucchini into 1/2-inch cubes, and cut the trimmed asparagus into 1-inch pieces. Rinse the spinach and set all prepped vegetables aside.
Heat the olive oil in a large Dutch oven over medium heat, then add the diced onion with a pinch of salt and cook for 4 to 5 minutes until softened and translucent. Add the minced garlic and cook for 1 to 2 more minutes, stirring frequently, until fragrant.
Add the sliced carrots and celery to the pot and cook for 4 to 5 minutes over medium heat, stirring occasionally. Stir in the dried thyme, Italian seasoning, and red pepper flakes (if using), and let the herbs toast in the oil for about 30 seconds.
Pour in the vegetable broth, scraping up any bits from the bottom of the pot, then add the canned diced tomatoes with their liquid and stir to combine. Bring to a gentle boil over medium-high heat, then reduce to medium-low and simmer uncovered for 10 minutes.
Add the diced zucchini, asparagus pieces, and peas to the simmering soup and stir gently to submerge. Continue simmering for 5 to 7 minutes until the zucchini is tender and the asparagus is bright green and cooked through but still has a slight bite. Season with salt and black pepper to taste.
Reduce heat to low, stir in the baby spinach, and cook for 1 to 2 minutes until fully wilted. Squeeze in the fresh lemon juice, stir to combine, and do a final taste check for seasoning.
Ladle the soup into bowls and top each with freshly chopped parsley or basil and a sprinkle of grated Parmesan cheese if desired. Serve immediately with crusty bread on the side.
Notes
Add the delicate spring vegetables (zucchini, asparagus, peas) in the last 5 to 7 minutes of cooking to preserve their color and texture — overcooking them leads to a mushy, dull-colored soup.
Don't skip the lemon juice at the end; it brightens the entire pot and brings all the flavors together without making the soup taste sour.
For a heartier meal, stir in a can of drained white beans or chickpeas, or cook small pasta shapes like orzo or ditalini directly in the simmering broth during the last 8 to 10 minutes.
To make it vegan, simply omit the Parmesan garnish. The soup base is entirely plant-based. Nutritional yeast makes a great vegan substitute for that savory, cheesy finish.
If you plan to freeze the soup, leave out the spinach and stir in fresh spinach each time you reheat a portion, as spinach turns dark and mushy after freezing.
Store leftovers in an airtight container in the refrigerator for up to 4 days or freeze for up to 3 months. The soup often tastes even better the next day as the flavors continue to develop.
Frozen peas and frozen spinach both work great in this recipe — no thawing required before adding them to the pot.
For extra flavor depth, add a Parmesan rind and a bay leaf to the broth while it simmers, then remove before serving.
Swap the yellow onion for leeks for a milder, more delicate flavor that feels especially springlike.
If the soup thickens too much in the fridge (especially if you added pasta), simply stir in a splash of vegetable broth when reheating to loosen it back up.