Preparation Cook first 4 ingredients in large pot of boiling salted water until almost tender, about 20 minutes. Add potatoes and continue cooking until all vegetables are very tender, about 15 minutes longer. Drain. Discard bay leaf. Return vegetables to same pot. Stir over medium heat to allow excess water to evaporate, about 2 minutes. Add butter; mash until vegetables are almost smooth. Mix in 1 tablespoon parsley. Season with salt and pepper. (Can be made 2 hours ahead. Let stand at room temperature. Rewarm over low heat, stirring often.) Transfer vegetables to bowl. Sprinkle with remaining 1 tablespoon parsley.
Preparation Cook first 4 ingredients in large pot of boiling salted water until almost tender, about 20 minutes. Add potatoes and continue cooking until all vegetables are very tender, about 15 minutes longer. Drain. Discard bay leaf. Return vegetables to same pot. Stir over medium heat to allow excess water to evaporate, about 2 minutes. Add butter; mash until vegetables are almost smooth. Mix in 1 tablespoon parsley. Season with salt and pepper. (Can be made 2 hours ahead. Let stand at room temperature. Rewarm over low heat, stirring often.) Transfer vegetables to bowl. Sprinkle with remaining 1 tablespoon parsley.