Now whether this is authentic challah, I don't know for sure, but it closely resembles other challah recipes I have. Anyway, it's really good, and Mack used to bring it every Easter Sunday morning for the choir to have for its between-services breakfast. The oleo makes this bread very tender.
I have streamlined the directions below. I have a file about bread-making basics if you'd like more detail about individual steps.
2 pkg yeast
1/2 c lukewarm water
1 T sugar
1 small to medium potato
Mix yeast and 1/2 c water and sugar and set aside to bubble. Boil potato and set aside 1 c of potato water. Mash potato, using other potato water (or milk, etc.). Set aside to cool to lukewarm.
1 stick oleo, melted and cooled to lukewarm (I use extra light olive oil)
1 t salt
1 T honey
3 eggs (I use Eggbeaters)
4 c flour
poppy seeds, optional
Mix all with mashed potatoes. If you want a more yellow bread (to point up the liberal use of eggs!), add some yellow food coloring (I do!). Add yeast mixture and stir well. Stir in 2 c flour and knead in rest, adding more if necessary.
Let rise 'til doubled. Punch down. Knead, trying not to add any more flour.
Divide dough in half. Cut each portion into 3 equal pieces. Let rest 10 minutes. Roll each into snakes the same diameter and length. Braid, pinching ends together well and "tucking under" the loaf to hide them. Place on sheet and brush each loaf with an eggwhite (or an egg yolk) mixed with 1 T water.
Let rise rise 'til doubled.
Bake at 375 degrees for 40-45 minutes or until golden.