In a small bowl, combine the warm water, 1 teaspoon of sugar, and active dry yeast. Stir gently and let sit for 5-10 minutes until foamy.
In a large mixing bowl, whisk together the flour, remaining sugar, and salt.
In a separate bowl, beat 2 eggs with the vegetable oil.
Add the yeast mixture and egg-oil mixture to the dry ingredients. Mix until a dough forms.
Turn the dough out onto a lightly floured surface and knead for about 8-10 minutes until smooth and elastic. Add flour as needed to prevent sticking, but keep the dough soft.
Place the dough in a lightly oiled bowl, cover with a clean kitchen towel or plastic wrap, and let it rise in a warm place for about 1.5 to 2 hours, or until doubled in size.
Punch down the dough and divide it into three equal portions.
Roll each portion into a long rope, about 12-14 inches long.
Braid the three ropes together by pinching one end and crossing the ropes over each other until you reach the end. Pinch the ends together and tuck them underneath the loaf.
Place the braided loaf on a parchment-lined baking sheet. Cover loosely with a towel and let rise for another 30-45 minutes until puffy.
Preheat the oven to 350°F (175°C).
In a small bowl, whisk together the egg yolk, honey, and 1 tablespoon water to make the egg wash.
Brush the egg wash evenly over the loaf, then sprinkle sesame seeds on top.
Bake the challah for 25-30 minutes, or until the bread is golden brown and sounds hollow when tapped on the bottom.
Remove from the oven and cool on a wire rack before slicing.