Place warm water and brown sugar in a small bowl. Sprinkle yeast over water and let soften for 5 minutes.
In a large mixing bowl, combine pumpkin, butter, and dry milk powder. Mix on medium speed for 1 minute.
Add yeast mixture and mix just until combined. Sift together flour, spice, and salt.
Gradually add flour mixture, a little at a time, to wet ingredients. Mix on low speed with a dough hook for 10 minutes making sure all flour has been incorporated.
Turn dough onto floured surface and knead 2-3 minutes until smooth.
Place in buttered bowl, cover with a cloth and let rise about 1 hour until double.
Punch down and let rest for a few minutes.