In a large bowl, combine 3 cups flour, sugar, yeast and salt. In a small saucepan, heat the squash, milk, water and butter to 120°-130°. Add to dry ingredients; beat just until moistened. Stir in enough remaining flour to form a soft dough.
Turn onto a floured surface; knead until smooth and elastic, about 6-8 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; divide into 24 pieces. Shape each into a ball. Place 2 in. apart on greased baking sheets. Cover and let rise in a warm place until doubled, about 45 minutes.
Bake at 400° for 15-18 minutes or until golden. Remove from pans to wire racks to cool.