Boil the required quantity of potatoes in their skins, drain and dry them, then peel and weigh them.

Pound them with the rolling-pin until they are quite free from lumps, and mix with them the flour in the proportion of seven pounds of flour to two and a half pounds of potatoes.

Add the yeast and knead in the ordinary way, but make up the bread with milk instead of water.

When the dough is well risen, bake the bread in a gentle oven.

Bake it a little longer than for ordinary bread, and, when it seems done enough, let it stand a little while, with the oven-door open, before taking it out.
Unless these precautions are taken, the crust will be hard and brittle, while the inside is still moist and doughy.