Pour the warm water into the bowl of a stand mixer and sprinkle the yeast over top of it. Allow the yeast to dissolve, about 5 minutes. Whisk in the milk, honey, and oil. Add the pumpkin puree and stir to combine. Add two cups of flour, the salt, and the pumpkin pie spice to the wet ingredients and stir until well integrated. Add an additional 2-1/2 cups of flour and, using the dough hook, knead the bread on medium speed for about 5 minutes or until the bread starts to become stretchy. Add additional flour to the bowl during the kneading process to get the dough the right texture. You are looking for a wet dough that pulls away slightly from the sides of the bowl.
Grease a large bowl and place the dough in it, covered with a piece of plastic wrap, to rise until doubled in size, about 1-1/2 hours. If the dough seems to have a hard time rising, move the bowl to a slightly warmer area of the kitchen. I like to let mine rise next to a warm oven.
Once doubled in size, dump the dough out onto a floured surface and divide into two equal pieces. Gently pat each piece of dough into a loaf-pan shaped rectangle and fold the two long edges to meet in the center of the dough. Rotate the dough 90 degrees and repeat. Fold the dough once more and gently form it into a loaf-shaped log. Place the dough into a greased loaf pan (8.5″ X 4.5″ X 2.75″) and cover loosely with plastic wrap. Preheat the oven to 425 degrees. Allow each loaf to rise a second time for about 45 minutes until the dough has domed an inch above the top of the pan.
In a small bowl, whisk the egg with 1 teaspoon of water. Brush a thin layer of this egg wash over top of each loaf and sprinkle with the pepitas. Place dough pans in the oven and immediately decrease the heat to 375 degrees. Bake for about 30 minutes or until the top of each loaf is golden brown and sounds a bit hollow when tapped. Cool in the pan on a cooling rack for ten minutes and then remove each loaf from the pan to continue cooling on their own. Once cooled completely, wrap in a bread bag or a large sheet of aluminum foil to keep fresh! Loaves can be frozen after baking if desired.