4 pounds white turnips, peeled and cut into 1/2 inch pieces
12 to 16 tablespoons butter
1 head of garlic, peeled
Salt and freshly ground black pepper
Bring a lot of salted water to a boil and parboil the turnips for 7 minutes; add the garlic and boil 1 minute longer; drain.
Melt 8 to 12 tablespoons of butter and cook the garlic and turnips, covered, over low heat for 5 minutes.
Transfer turnips and garlic to a food processor and puree until smooth, adding 4 more tablespoons butter with the machine turned on. Season well with salt and pepper and, if made in advance, reheat in a double boiler.