Mashed Root Vegetables with Horseradish

In a large saucepan of boiling salted water cook the turnips and the parsnips for 10 minutes, add the potatoes, peeled and cut into 1/2-inch pieces, and boil the vegetables for 10 to 12 minutes, or until they are tender. While the vegetables are cooking, in a small saucepan heat the cream, the butter, and the horseradish to taste over low heat until the mixture is hot and keep it warm. Drain the vegetables, in the pan cook them over high heat, shaking the pan, for 30 seconds, or until any excess liquid is evaporated, and remove the pan from the heat. Add the cream mixture to the potato mixture, straining it through a fine sieve and pressing hard on the solids if desired. In a bowl mash the vegetables with a potato masher until they are smooth and stir in salt and pepper to taste.