Mashed Plantains with Leeks and Fresh Herbs

• 7 cups water
• 1 cup low-salt chicken broth
• 4 unpeeled large semi-ripe (yellow-black) plantains, ends trimmed, each cut crosswise into thirds

• 4 tablespoons (1/2 stick) unsalted butter, divided
• 2 tablespoons extra-virgin olive oil
• 1 large leek (white and pale green parts only), finely chopped
• 2 tablespoons minced fresh thyme
• 1 tablespoon minced fresh Italian parsley

• 1 cup sour cream
• 1 1/2 teaspoons ground cumin
• 2 tablespoons chopped pecans

Bring 7 cups water and broth to boil in heavy large pot. Add plantains. Reduce heat to medium; cover and simmer until plantains are very tender and yellow-orange (some may begin to come out of peel), about 20 minutes. Drain, reserving 1 cup cooking liquid. Cool plantains 10 minutes. Remove peel using hands or small paring knife. Transfer plantains to large glass bowl. Add 1/2 cup of reserved cooking liquid and mash plantains until smooth, adding more liquid by tablespoonfuls to thin mixture, if desired. Set aside.

Melt 2 tablespoons butter with olive oil in medium nonstick skillet over medium heat. Add leek and sauté until tender but not browned, about 6 minutes. Stir in thyme and parsley. Add leek mixture to mashed plantains; stir to blend. (Can be made 1 hour ahead. Let stand at room temperature. Microwave on high until heated through before continuing.)

Mix sour cream and cumin into hot plantains. Season with salt and pepper. Cut 2 tablespoons butter into small cubes. Scatter butter and pecans over; serve.