Mix all of the dry ingredients, except for the salt, in the stand mixer bowl.
Attach the kneading hook and mix on slow speed.
Gradually add oil, water, and egg while mixing.
Add salt and knead for 4 minutes until dough is unified.
Form the dough into a ball shape and let this rise in a greased bowl for an hour.
Divide the dough into 2 pieces and let this rise again for half an hour.
Divide each pieces to smaller pieces and create strands to braid the challah.
Braid the strands to challahs. (In the pictures I made round challahs from 4 strands each)
Heat the oven to 160°C / 325°F degrees with no fan - upper and lower heat.
Brush the 2 braided challahs with the egg wash and let this rise again for another half an hour - if you are in a hurry, you can skip this step.
Make another layer of egg wash and sprinkle all of the garnish seeds.
Bake for 40-50 minutes –but pay attention after 40 minutes if the bread looks very golden then take them out of the oven!
Serve and Shabbat Shalom!