Cassava Root Soufflé (Budin de Yuca)

Ingredients

 * 1 pound cassava (yucca) root
 * salt, freshly ground pepper
 * 6 tablespoons butter
 * 1 cup milk
 * 4 egg yolks
 * 5 egg whites

Directions

 * 1) Peel the cassava (yucca) root under cold running water, as it discolors quickly.
 * 2) Slice it and drop it into a saucepan of salted water. Bring to a boil, lower the heat, cover, and simmer until tender, about 30 minutes.
 * 3) Drain the cassava, mash, season to taste with salt and pepper, and beat in the butter.
 * 4) Heat the milk and stir it gradually into the mashed vegetables until it has the consistency of mashed potatoes.
 * 5) Use a little more hot milk if necessary.
 * 6) Beat in the egg yolks one by one.
 * 7) Beat the egg whites with a pinch of salt until they stand in firm peaks.
 * 8) Fold them into the vegetable mixture lightly but thoroughly and pour into a 2-quart souffle dish.
 * 9) Bake in a preheated moderate (350°F) oven for 35 minutes or until well puffed and lightly browned.
 * 10) Leave whole or cut into wedges and serve immediately.