In a large bowl, dissolve yeast in warm water. Add 1 teaspoon brown sugar; let stand for 5 minutes. Add the milk, pumpkin, butter, orange zest, salt, remaining sugar and 2 cups flour. Beat on medium speed for 2 minutes. Stir in enough remaining flour to form a soft dough.
Turn onto a floured surface; knead until smooth and elastic, about 10 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 1 hour.
Punch dough down. Turn onto a lightly floured surface; knead until smooth and elastic, about 6-8 minutes.
Divide into six portions. Divide each into 12 pieces. Shape each into a ball; place three balls in each greased muffin cup. Cover and let rise until doubled, about 30 minutes.
Brush rolls with egg. Bake at 400° for 20-25 minutes or until golden brown. Remove from pans to wire racks to cool.