I got the recipe from another blog, who in turn got it from some other blog... and so on.
¼ cup whole milk, at room temperature2
½ tsp active dry yeast
1 cup pumpkin puree
1/3 cup sugar
1 cup bread flour
Combine the milk and yeast in the bowl of a standing mixer fitted with a paddle attachment ans whisk until the yeast is dissolved. Let stand for 5 minutes, then stir in the pumpkin puree, sugar, and flour, forming a thick batter. Cover with plastic film and let rest in a warm environment until bubbles form, 30-40 minutes.
For the Dough:
5 cups bread flour
2 tsp salt
6 large eggs, lightly beaten
½ lb(2 sticks) unsalted butter, softened
1.Add the flour ans salt to the sponge, then add the eggs. Mix on low speed for 2 minutes, or until the eggs are absorbed. Increase speed to medium and knead the dough for 5 minutes. The dough will begin to slap around. Hold on to the mixer when necessary.
Whisk together the egg and yolk. Gently brush the surface of the dough with the egg wash.