Steam pumpkin, covered, 15 minutes or until tender; set aside.
Bring broth to a simmer in a saucepan (do not boil). Keep warm over low heat.
Coat a large saucepan with cooking spray; place over medium heat until hot. Add onion and garlic; sauté 5 minutes. Add rice; sauté 1 minute. Add wine; cook 1 minute or until liquid is nearly absorbed, stirring constantly. Add warm broth, 1/2 cup at a time, stirring constantly until each portion of broth is absorbed before adding the next (about 18 minutes total). Stir in pumpkin; cook 2 minutes or until thoroughly heated. Remove from heat; stir in cheese and remaining ingredients. Serve immediately.