Fresh basil adds a bright spark to this vinegary, vegetable-stuffed soup, full of the traditional flavors of the Mediterranean. Alternatively, pesto adds a nutty richness to the soup.

2 tablespoons extra-virgin olive oil
1 large onion, diced
1-3 teaspoons hot paprika, or to taste
2 14-ounce cans vegetable broth
4 medium plum tomatoes, diced
1 medium yellow summer squash, diced
2 cups diced cooked potatoes (see Cooking Tip)
1 1/2 cups green beans, cut into 2-inch pieces
2 cups frozen spinach (5 ounces)
2 tablespoons sherry vinegar or red-wine vinegar
1/4 cup chopped fresh basil or prepared pesto

Heat oil in a Dutch oven over medium heat. Add onion, cover and cook, stirring occasionally, until beginning to brown, about 6 minutes. Add paprika and cook, stirring, for 30 seconds. Add broth, tomatoes, squash, potatoes and beans; bring to a boil. Reduce heat to a simmer and cook, stirring occasionally, until the vegetables are just tender, about 12 minutes. Stir in spinach and vinegar; continue cooking until heated through, 2 to 4 minutes more. Ladle soup into bowls and top with fresh basil or a dollop of pesto.

Ingredient Note: Convenient cooked and diced potatoes can be found in the refrigerated section of the produce and/or dairy department of the supermarket.

To Make Ahead: Cover and refrigerate for up to 2 days.