Apple Challah

from "A Blessing of Bread: Recipes and Rituals, Memories and Mitzvahs" by Maggie Glezer.

2 envelopes (0.25 ounce each) or 1 tablespoon plus 1 1/2 teaspoons instant yeast
5 cups bread flour
1 cup warm water
3 large eggs
1/3 cup vegetable oil, plus extra for oiling pan and topping
2 1/2 teaspoons table salt
1/2 cup sugar, plus extra for sprinkling
3 large or 4 medium (about 2 1/2 pounds) baking apples (preferably Braeburn)

1. In a large bowl, whisk together yeast and 1 cup of the flour. Then
   whisk in warm water until smooth. Let stand uncovered 10 to 20 minutes,
   or until it begins to ferment and puff up slightly.
2. Whisk eggs, oil, salt and sugar into puffed yeast slurry until eggs are
   well incorporated and salt and sugar have dissolved. With your hands or
   a wooden spoon, stir in remaining 4 cups flour all at once. When the
   mixture is a shaggy ball, scrape it out onto your work surface and
   knead until smooth and firm, no more than 10 minutes. (Soak mixing bowl
   in hot water to clean and warm it for fermenting dough.) If dough is
   too firm to knead easily, add a tablespoon or two of water. If dough is
   too wet, add a few tablespoons of flour. The dough should feel smooth,
   soft and only slightly sticky.
3. Place dough in the clean, warmed bowl and cover with plastic wrap. Let
   dough ferment for one hour, or until just slightly puffed.
4. Meanwhile, peel, quarter and core apples. Cut each quarter lengthwise
   in half. Then cut each slice crosswise in half for medium apples and in
   thirds for large, ending with large, squarish chunks. Measure 4 1/2
   heaping cups of chunks (reserving extra for another use) and transfer
   them to a covered container.
5. After fermenting, sprinkle dough and work surface with flour. Cut dough
   into two equal pieces, keeping one piece covered while working with the
   other. Roll out dough into a 16-inch square about 1/8-inch thick.
   Scatter 1 heaping cup apples over center third of dough. Fold up bottom
   third to cover. Press dough into apples to seal around them. Scatter
   another heaping cup apples over lower half of folded and filled dough
   and fold top of dough over both layers to create a very stuffed letter
   fold. Press down on dough to push out air pockets and to seal dough
   around apples.
6. Roll dough up from short side into a chunky cylinder.
   Push dough into a bowl, smooth side up. Cover with plastic wrap. Repeat
   with other piece of dough, using a second bowl. Let both doughs ferment
   for about one hour, or until slightly risen and very soft.
7. Oil two 8-inch round cake pans. Using as much dusting flour as needed,
   pat each dough half into a roughly round shape, keeping smooth side
   intact on top. You will not be able to deflate dough much because of
   apples. Slip dough into pans smooth side up and cover well with plastic
   wrap. (The loaves may now be refrigerated up to 24 hours, which will
   intensify flavor.) Let loaves proof until they have risen over edges of
   pans, about 30 minutes (or up to 90 minutes if previously refrigerated.)
8. Arrange oven rack in lower third position and preheat oven to 350 F.
9. When loaves have risen and do not push back when gently pressed with a
   finger but remain indented, brush each with generous tablespoon of oil.
   Sprinkle with a few tablespoons sugar.
10. Bake until very well browned,
    45-55 minutes. (After the first 40 minutes, switch the pans from front
    to back and bake 5-15 minutes more.) Remove loaves from oven, unmold
    and cool on a rack.

Makes two 9-inch round challahs