In the bowl of an electric mixer, using a whisk, combine the flour, sugar, salt and yeast.

In a mixing bowl, whisk the warm water, oil, eggs, and egg yolks.

On low speed, using the paddle attachment, add the liquid ingredients into the electric mixer with the dry ingredients.

Mix the dough on medium speed until well combined. Add more water, a tablespoon at a time, if the dough is too dry.

Place the dough onto an unfloured work surface and knead well until smooth and elastic, about 2-3 minutes. Place the dough in a large mixing bowl that has been sprayed with nonstick cooking spray. Flip the dough over so the greased side is facing up.

Cover the bowl of dough tightly with plastic wrap. Allow the dough to rise in a warm place until it has doubled in volume, about 1 hour.

Using a dough cutter, divide the dough into 4 equal pieces by cutting the dough into halves then quarters. Roll each piece on a work surface until it forms a log which is about 18 inches long.

On an unfloured work surface, place 2 of the logs parallel to each other, approximately an inch apart.

Lightly cross the first 2 ropes right over the left. Do the same for the remaining 3 pairs of ropes.

Take one rope from one pair and one rope from the adjacent pair and cross them left over right. Do the same for the remaining 3 pairs.

Tuck all loops and ends gently under the challah.

Transfer challah to a baking pan lined with parchment paper and sprinkled with cornmeal.

Lightly cover challah with greased plastic wrap or a clean kitchen towel and allow the challah to rise until it has doubled in size, about 1 hour.

While the dough is rising, preheat oven to 375°F. Using a pastry brush, egg wash the challah.

Bake the challah for 25 to 30 minutes until nice and brown.