Potatonik (Yeasted Potato Kugel)

• Sponge
• 1 cup warm water
• 1.5 (1/4 ounce) packages active dry yeast (scant 1 1/2 Tbsp)
• 1 1/2 cups bread flour unbleached all-purpose flour
• Dough
• 3/4 lb potato, skins on (about 1 1/2 medium potatoes)
• 6 ounces yellow onions, ground or grated (1 1/4 medium onions)
• 1 small stale rolls (torn or crumbs) or 2 slices old bread (torn or crumbs)
• 1/2 cup bread flour or 1/2 cup unbleached all-purpose flour
• 1 1/2 teaspoons salt
• scant 1/2 tsp baking powder
• 1/4 teaspoon freshly ground black pepper (to taste)
• 1/2 cup vegetable oil
• 1/2 cup lightly beaten egg (about 2 extra-large eggs)
• shortening, for greasing pans

1. Sponge: In a medium bowl sprinkle the yeast over the warm water; stir to dissolve. Add the flour and mix until smooth. Cover and set aside until it puffs up (20 to 25 minutes).
2. Dough: Stir down the Sponge. Scrub the potatoes, then grind or grate them with the skins on or process in a food processor into a coarse chop; do not puree. Transfer to a large bowl. Add the ground potatoes and onion to the Sponge and stir until blended. Add the stale roll, flour, salt, baking powder, and ground pepper; mix or pulse only until incorporated. Add the oil and egg and mix well. Drop the mixture out into 3 well-greased 8- or 9-inch loaf pans. Each loaf should weigh about 15 ounces. Leave room for expansion - the potatonik will rise in the oven.
3. Baking: Bake with steam (see below) in a preheated 360 F oven until the crust is brown and feels firm when gently pressed in the center with your fingertips (about 1 hour). Let cool on a wire rack covered with a cloth for 5 minutes to allow the loaves to steam. Invert and tap out onto the rack. Serve warm. DO AHEAD: Potatonik can be refrigerated for several days or frozen for 1 to 2 weeks. Reheat at 325 F until warm. When reheating, I like to bake it for 35 to 45 minutes to develop a hard crust.
4. Steam in Baking: Place an empty roasting pan or other heavy pan on the floor of the oven 5 to 10 minutes before baking, so it gets hot. Brush the tops of the loaves with water, place in the oven and carefully toss 6 to 8 ice cubes into the hot pan, or pour in 1 cup boiling water and immediately close the oven door. CAUTION: When using boiling water, wear a glove and keep your face away from the open oven door, since there will be a burst of live steam when the boiling water hits the hot pan. Do not open the door to peek or the steam will escape.

water, active dry yeast, bread flour, dough, potato, yellow onions, stale rolls, bread flour, salt, baking powder, freshly ground black pepper, vegetable oil, egg, shortening

Taken from www.food.com/recipe/potatonik-yeasted-potato-kugel-435857 (may not work)