Challah Bread

1 Tbsp. dry yeast
1 1/2 c. water
1/4 c. granulated sugar
1/4 c. vegetable oil
1 tsp. salt
2 eggs, beaten well
Pinch of Saffron (optional)
1 egg yolk, beaten well
1/4 tsp. water
Sesame seeds

Place yeast and water in a large bowl.  Stir slightly to dissolve.  Add sugar, oil, salt, beaten eggs, saffron and 2 1/2 cups flour. Beat well.  Add enough remaining flour to make a soft dough and knead until smooth.  Place in a greased bowl.  Cover and let rise until double in bulk (30-40 minutes).  Punch down dough and divide into 6 pieces.  Roll each piece into a long rope, 18-20 inches long and 1 inch in diameter.  Braid three of the ropes together.  Repeat with the remaining 3 pieces of dough.  Place on a greased cookie sheet.  Mix egg yolk with 1/4 teaspoon water and brush over braids.  Sprinkle with sesame seeds.  Cover and let rise 30 minutes,  Bake at 375 degrees about 30-35 minutes.