Creamy Turnip Puree with Walnuts, Anchovies, and Parsley

6 pounds medium turnips, peeled, quartered
3 garlic cloves, peeled
1 1/2 cups whipping cream
1/4 cup (1/2 stick) butter
1/4 cup olive oil
6 anchovy fillets
1 cup walnuts, coarsely chopped
1/2 cup finely chopped fresh Italian parsley

Cook turnips and garlic in large pot of boiling salted water until turnips are very tender, about 30 minutes. Drain. Return turnips and garlic to pot; stir over medium-high heat until dry, about 2 minutes. Working in batches, puree turnips, garlic, 1 1/2 cups cream, and butter in processor until smooth. Return puree to pot. Season to taste with salt and pepper. Add more cream if necessary to reach desired consistency. (Can be made 1 day ahead. Cover and refrigerate.)

Heat olive oil in heavy medium skillet over medium-low heat. Add anchovies and cook, mashing with back of wooden spoon until dissolved, about 1 minute. Add walnuts and cook until slightly crisp, about 5 minutes. Stir in parsley. Rewarm turnip puree over medium heat, stirring frequently. Transfer to serving bowl. Spoon walnut mixture over.