In a small bowl, dissolve the yeast and a pinch of sugar in warm water. Let it sit for about 5 minutes until it becomes frothy and activated.
In a large mixing bowl, combine the flour, sugar, and salt. Make a well in the center and add the yeast mixture, eggs, egg yolks, and vegetable oil.
Mix the ingredients with a wooden spoon until a shaggy dough forms. Then, transfer the dough onto a floured surface and knead it for about 8-10 minutes until it becomes smooth and elastic.
Place the dough in a greased bowl, cover it with a clean kitchen towel, and let it rise in a warm place for about 1-2 hours or until it doubles in size.
Once the dough has risen, punch it down to release any air bubbles. Divide the dough into three equal portions.
Roll each portion into a long rope, approximately 16-18 inches in length. Ensure that the ropes are of equal thickness.
Pinch the ends of the three ropes together, then braid them by crossing the right rope over the center rope, then the left rope over the new center rope. Continue this pattern until the entire loaf is braided.
Tuck the ends under the loaf and transfer it onto a parchment-lined baking sheet. Cover it with the kitchen towel and let it rise for another 30-45 minutes until it puffs up.
Preheat the oven to 350°F (175°C). In a small bowl, beat an egg with a splash of water. Brush the egg wash over the loaf, then sprinkle sesame seeds, poppy seeds, or coarse salt on top for added flavor and visual appeal.
Bake the challah bread for 25-30 minutes or until it turns golden brown and sounds hollow when tapped on the bottom.
Remove the bread from the oven and let it cool on a wire rack before slicing and serving.