Now that my starter is 6 months old and stronger, I made a challah raised completely with starter (last time I added yeast). The results were beautiful, and Mr. ETB who isn't typically a fan of egg breads really loved it.
What I did:
Sponge-1 cup fed starter
2 cups water
2 heaping cups strong (bread) flour
Mix well, cover and let ferment 18-24 hours (mine went 20).
To starter add:
1/2 cup granulated sugar
A generous pinch saffron
2 teaspoons table salt
1/4 cup corn oil
3 large eggs
2-3 cups strong flour or enough to make a dough that isn no longer too sticky to knead
Work the dough until smooth. Place in oiled bowl to rise-about 8 hours.
Divide dough into 4 pieces. Let rest 30 minutes, covered.
Work into ropes and braids. Place on a buttered baking sheet. Cover lightly. Let rise until almost doubled-about 2 hours.
Preheat oven to 375 degrees F.
Brush with egg yolk and water wash. Bake 20 minutes. Remove from oven, brush again with wash and bake another 20-25 minutes or until deeply golden. I baked mine to an internal temperature of 200 degrees F. Cool on rack. Makes one very large loaf.