17 ounces red-skinned potatoes (about 3 medium), peeled
5 cups water
3/4 cup sugar
6 tablespoons (3/4 stick) butter, room temperature
4 teaspoons coarse salt
1/2 cup warm water (105°F to 115°F)
3 envelopes dry yeast
Pinch of sugar
4 large eggs
8 cups (about) unbleached all purpose flour
Cornmeal
3/4 cup golden raisins (optional)
1 egg, beaten to blend (glaze)
Sesame or poppy seeds
Combine potatoes and 5 cups water in large pot. Cover and boil until potatoes are very tender, about 40 minutes. Ladle 1 1/4 cups cooking liquid into small bowl and reserve; cool reserved liquid to lukewarm. Drain potatoes. Transfer potatoes to medium bowl and mash potatoes until smooth. Place mashed potatoes in strainer set over large bowl of electric mixer. Using rubber spatula, press mashed potatoes through strainer. Add 3/4 cup sugar, butter, 4 teaspoons salt and 1 1/4 cups reserved cooking liquid to mashed potatoes. Using dough hook, beat until well blended.
Combine 1/2 cup warm water, yeast and pinch of sugar in small bowl. Let stand until foamy, about 10 minutes. Add to potato mixture and beat to blend. Beat in 4 eggs. Mix in enough flour, 1 cup at a time, to form soft dough. Turn out dough onto generously floured surface. Knead until smooth and elastic, adding more flour as necessary to form soft elastic dough, about 10 minutes. Lightly oil large bowl. Add dough, turning to coat. Cover bowl with plastic wrap, then towel. Let dough rise in warm draft-free area until doubled in volume, about 1 hour.
Oil 2 large baking sheets. Sprinkle generously with the cornmeal. Turn out dough onto floured surface. Divide dough in half; knead each piece lightly. If desired, knead raisins into 1 piece of dough. Divide each dough piece into 3 equal portions. Roll out each portion between work surface and palms of hand to 15-inch-long rope. Form into braids, using 3 ropes for each braid. Tuck ends under and pinch ends together. Place 1 loaf on each baking sheet. Cover with towel and let rise in warm draft-free area until almost doubled, about 30 minutes.
Preheat oven to 400°F. Brush loaves with egg glaze. Sprinkle with sesame seeds or poppy seeds. Bake 15 minutes. Reduce oven temperature to 350°F. Continue baking until loaves are deep golden brown and sound hollow when tapped on bottom, about 25 minutes longer. Transfer to racks and cool completely. (Can be made ahead. Wrap tightly in foil and freeze up to 2 weeks.)
Bon Appétit November 1994
Makes 2 Loaves
