In a large bowl mix flour, potato water and yeast. Cover and let sit for 45 mins.
3 1/3 cups flour
1 3/4 tsp salt
1/3 cup sugar
1/4 cup butter
4 large eggs
Add flour and butter to the sponge ingredients. Mix until combined then add the rest of the ingredients. Turn dough out onto your work surface and knead. Dust with flour and knead again.
Place dough into a well greased bowl and cover it.
2 ways to continue: 1. Let rise in a warm place for 1 1/2 hours OR 2. Place covered bowl in the refrigerator for a few hours.
I chose option 2 and left it in the fridge for 18 hours. I made it the night before and baked it when I got home from work the next day. Perfect!
Either way you choose - Next, punch down dough and divide it in to 3 equal pieces. Roll the 3 pieces into 12-14 inch long ropes. On your well greased/silpat covered baking sheet braid the 3 pieces together.
Let rise for 1 hour, until doubled in size.
Preheat oven to 375 degrees.
One egg, beaten with a little salt.
Before baking, brush loaf with egg wash and sprinkle with sesame seeds or poppy seeds.
Bake for 40 mins or until loaf sounds hollow when tapped on the bottom.