Mix the ingredients for the sponge and allow to rise for 2 - 3 hours.
Mix the flour, 7/8 of the eggs (190 g), and the sugar. Allow to rest for 5 minutes or more.
After the rest, add the yeast, salt, and ascorbic acid, the sponge, remaining egg and mix till dough pulls away from the sides of the bowl.Dough temp should be about 75F (24C). Allow to rest another half hour.
Knead the butter and then add to the dough in chunks. Dough should pull away from the sides of the bowl again. Allow to raise another hour (maybe refrigerated). Punch down and allow 2nd rise at 80F (27C) for an hour and a half.
Turn out onto floured board and fold a few times.
Divide, shape, and allow to rise one last time. Brush with egg wash. Bake at 425F (27C) for 15 - 30 minutes depending on the size of the product.