1 package active dry yeast
¼ cup plus a pinch of sugar
1 ¼ cups warm water (110° to 115°F)
2 teaspoons salt
¼ pound unsalted margarine, melted
4 ½ to 5 cups flour
Poppy Seed-Onion Filling
1 ½ cups finely chopped onion
½ cup poppy seeds
½ teaspoon salt
5 ½ tablespoons unsalted margarine, melted
Combine all the ingredients in a bowl. Set aside.
Dissolve the yeast with a pinch of sugar in ½ cup of the warm water.
In the bowl of an electric mixer, blend 1 of the eggs, the ¼ cup sugar, salt and margarine and remaining ¾ cup water. Blend in the yeast mixture. Add the flour, 1 cup at a time, mixing until the dough comes together. Pour onto a floured board and knead, adding additional flour, a little at a time, until the dough has a smooth and elastic consistency, 5 to 10 minutes.
Place the dough in an oiled bowl, oil the top of the dough, cover with a towel, let it rise in a warm place until doubled, about 1 hour.
Punch down the dough. Divide it in half. Roll each half out to a 20 x 4 inch rectangle. Spread each rectangle with the filling (reserving ¼ cup for the top) to within ½ inch of the edges. Roll each rectangle lengthwise, jelly-roll fashion, to enclose the filling, forming a long rope. Twist the two ropes together. Form dough into a ring. Pinch ends to seal and place on an oiled baking sheet. Cover and let rise in warm place until doubled, about 45 minutes.
Preheat oven to 350°F.
Lightly beat the remaining egg and brush it over the challah. Sprinkle the challah with the reserved filling. Bake for 40 minutes, or until the loaf is golden and sounds a hollow when tapped. Transfer to rack to cool.