Creamy Zucchini-Chickpea Soup with Spinach

Heat oil in a large pot over medium-high heat. Add onion and cook, stirring often, until softened, 3 to 4 minutes. Add zucchini, garlic, cumin and bay leaf; cook, stirring often, until fragrant, about 1 minute. Add broth and chickpeas; bring to a simmer over high heat. Reduce heat to maintain a lively simmer and cook, covered, until the zucchini is tender, 15 to 20 minutes. Discard the bay leaf. Add spinach and stir until it has wilted.

In batches, puree the soup in a blender or food processor. (Use caution when blending hot liquids.) Return the soup to the pot. Add lemon juice, tahini, salt and pepper; whisk until the tahini is incorporated.

Ladle the soup into bowls. Add a dollop of yogurt to each one and swirl it into the soup. Sprinkle with herbs, if desired.