4 ounces (1 stick) unsalted margarine
3 ½ cups unbleached bread flour, plus more for surface
¾ cup warm water
2/3 cup honey
2 large eggs plus 3 large egg yolks
2 teaspoons active dry yeast (from one ¼-ounce envelope)
2 teaspoons coarse salt
1 ½ tart green apples, preferably Granny Smith, peeled and cut into ¼-inch-thick slices (about 1 ¾ cups)
More margarine for pan and bowl.
1. Spray a large bowl with non stick spray, melt 4 tablespoons margarine in a saucepan over medium-low heat; let cool. Combine 2 tablespoons melted margarine, the flour, water, 1/3 cup honey, the eggs and yolks, yeast, and salt in a large bowl. Mix until dough forms. Turn dough out onto a floured surface, and knead until smooth, about 10 minutes.
2. Transfer dough to greased bowl, and brush with 1 tablespoon melted margarine. Cover with plastic. Let rise in a warm place until dough almost doubles in volume, about 1 ½ hours.
3. Turn dough out onto a floured surface. Pat into a 8 ½-by-14-inch rectangle. Top with apples; knead to incorporate. Return to bowl. Brush with remaining tablespoon melted margarine; cover. Let rise again in a warm place until dough almost doubles in volume, about 1 hour more.
4. Preheat oven to 375 degrees, with rack in lowest position. Grease a 9-inch round cake pan. Roll dough into a rope (about 24 inches) on a floured surface. Coil into a circle, and transfer to pan. Let rise again until dough almost doubles in volume, about 45 minutes more.
5. Heat remaining 4 tablespoons margarine and 1/3 cup honey in a saucepan over medium-low heat until melted. Brush dough with half the honey-margarine. Bake until golden brown and firm, about 35 minutes.
6. Brush challah with the remaining honey-margarine. Let cool in pan on a wire rack for 30 minutes. Turn out loaf from pan, and let cool.