Peel squash and cut into 3/4- to 1-inch chunks. Heat butter in large skillet or saucepan with tight-fitting lid over MED heat. Add onion. Sauté until onion is golden.
Add squash, figs, sherry, broth, rosemary and salt. Cover, bring to a boil, then reduce heat and simmer gently for 10 minutes or until squash is tender. If liquid remains, remove figs and vegetables with slotted spoon to serving bowl; simmer uncovered until liquid is reduced to 3 to 4 T. Pour liquid over squash mixture.