Ingredients
1 tablespoon olive oil
2 large leeks, whites and pale-greens only, halved lengthwise, thinly sliced (about 2 1/2 cups)
Kosher salt and freshly ground black pepper
2 large garlic cloves
2 teaspoons dried marjoram
2 1/2 pounds broccoli, stems peeled, chopped into 1-inch pieces (about 12 cups)
1 quart low-sodium chicken or vegetable broth
1 pound fresh flat-leaf spinach, trimmed
Plain yogurt (for serving)
Preparation
Heat oil in a large heavy pot over medium-high heat. Add leeks, season with salt and pepper, and cook, stirring occasionally, until leeks are wilted, about 5 minutes. Add garlic and marjoram; stir until aromatic, about 1 minute. Add broccoli; stir until coated and bright green, about 2 minutes. Add broth; cover with lid slightly ajar and bring to a boil. Reduce heat and simmer until broccoli is tender, 5-8 minutes. Add spinach to pot. Stir until wilted, about 2 minutes. Working in batches, purée soup in a blender, adding water by 1/4-cupfuls if too thick, until very smooth. Return soup to pot. Season to taste with salt and pepper; thin with more water if needed for consistency. Divide among bowls. Spoon a dollop of yogurt on top. Season with pepper.
