extra-virgin olive oil • medium leeks, trimmed and cut into ½-inch pieces (1 lb, about 4 cups) • medium parsnips, peeled and cut into ½-inch pieces (2 lbs, about 4 cups) • kosher salt • Black pepper • bay leaf • ground turmeric • garlic cloves, minced • water, chicken broth or vegetable broth • Extra-virgin olive oil, crème fraîche or yogurt, and lemon juice for garnish (optional)