2 tablespoons olive oil
1 large leek, white and light green parts only, thinly sliced into half-moons (about 3 cups)
12 ounces waxy potatoes, such as new potatoes or creamers, peeled and diced into 1/2-inch pieces
1/2 teaspoon kosher salt, plus more to taste
1/4 teaspoon freshly ground black pepper
6 cups low-sodium chicken or vegetable broth
2 cups (10 ounces) sweet green peas, fresh or frozen (if frozen, do not defrost)
2 cups packed fresh baby spinach leaves
1/4 cup coarsely chopped fresh flat-leaf parsley
2 tablespoons coarsely chopped fresh dill
Note: Feel free to vary the vegetables based on what you have on hand, swapping onion for the leeks, parsnips or carrots for the potato, or using snow peas, baby kale, and basil for the green vegetables and herbs, for example.
In a soup pot over medium heat, heat the oil until shimmering. Add the leek and cook, stirring occasionally, until softened but not browned, 4 to 5 minutes. Stir in the potatoes, salt and pepper. Add the broth and bring to a boil, then reduce the heat to medium-low and simmer, uncovered, until the potatoes are tender, about 8 minutes.
Stir in the peas and continue to simmer until they turn bright green and just tender, 2 to 5 minutes. Add the spinach and cook until just wilted but still bright green, 30 seconds. Stir in the herbs, then ladle into bowls and serve hot.