Mix oil, salt and sugar. Stir in boiling water until dissolved. Add cold water. Dissolve yeast into 1/3 cup warm water (it may look a little lumpy). Set aside.
Add eggs, cinnamon and vanilla to mixture. Mix in dissolved yeast.
Add 2-3 cups whole wheat flour (how much whole wheat flour to add depends on your taste). Mix in 5-6 cups bread flour until dough is no longer sticky.
Let rise in a warm place 1 1/2 hour, or until doubled.
Braid challah and let rise 45 minutes.
Bake at 325 degrees until browned and bottom taps slightly hollow.
[We don't like egg brushed on top, but it could be added.]