Challah

In a large bowl or the bowl of a heavy-duty mixer, combine the lukewarm water, yeast, 1/2 cup bread flour, eggs, egg yolks, oil, sugar, and salt. Let stand until the yeast is dissolved, about 5 minutes.

Mixing by hand or on low speed until thoroughly blended, gradually stir in the remaining 2 1/2 cups bread flour. Knead for about 8 minutes by hand or with the dough hook on low to medium speed until the dough is smooth and elastic and no longer sticks to your hands or the bowl. Transfer the dough to an oiled bowl and turn once to coat with oil. Cover with plastic wrap and let rise in a warm place until doubled in bulk (1 to 1 1/2 hours).

Punch down the dough, knead briefly, and return to the bowl. Refrigerate, covered, until it has nearly doubled in size (2 to 12 hours). The dough is ready to be shaped.

Divide dough into 3 pieces. Roll into balls, let rest for 10 minutes.

Grease a baking sheet and sprinkle with cornmeal. Roll each ball into ropes and dust with flour. Braid the entire length of dough, tucking the ends under.

Beat the egg with the salt for the egg wash. Brush over the loaf. Loosely cover the braid with oiled plastic wrap and let rise for about 45 minutes.

Preheat oven to 375 degrees F. Brush the loaf again with egg wash and sprinkle with poppy seeds. Bake until the crust is golden brown, 30 to 35 minutes. Cool on a rack.