Heat milk, butter, sugar and alt until butter is melted.
Cool to lukewarm. Dissolve yeast in warm water in marge mixing bowl.
Stir in milk mixture, squash and 2 cups of the flour.
Beat until smooth. Mix in enough remaining flour to make dough easy to handle.
Turn dough onto lightly floured surface; knead until smooth and elastic, about 5 minutes.
Place in greased bowl, turn greased side up. Cover; let rise in warm place until double, about 1 1/2 hours.
Punch down dough. Shape into 1 inch balls. Place 3 balls in each of 24 greased muffin cups. Let rise until double, 30 to 45 minutes.
Heat oven to 400 degrees. Bake until light brown, 15 to 20 minutes.