Ingredients

• 3 tablespoons extra-virgin olive oil
• 2 cups chopped onions
• 1 large russet potato (about 14 ounces), peeled, cut into 1-inch pieces
• 2 pounds plum tomatoes, seeded, cut into 1-inch pieces (about 6 cups)
• 3 cups (or more) water
• 1 cup (loosely packed) fresh basil leaves plus 4 teaspoons chopped fresh basil

Instructions

1. Heat oil in heavy large pot over medium heat. Add onions and sauté until golden, about 15 minutes. Add potato and sauté until light brown, about 10 minutes. Add tomatoes and stir until juices form, about 5 minutes. Add 3 cups water; bring to boil. Reduce heat to low, cover and simmer until potato is tender, about 25 minutes.
2. Working in batches, puree soup in blender until smooth. Return soup to pot. Thin with additional water, if desired. Stir in 1 cup basil leaves. Simmer uncovered 5 minutes. Season soup to taste with salt and pepper. Ladle soup into 4 bowls. Sprinkle each with 1 teaspoon chopped basil.