In a medium saucepan bring broth to boiling. Cover and reduce heat until broth just simmers. Meanwhile, in a large nonstick skillet heat oil over medium heat. Add garlic; cook and stir for 15 seconds. Add squash and rice; cook and stir 1 minute more.
Slowly and carefully add 1/2 cup of the hot broth and the saffron or turmeric to rice mixture, stirring constantly. Continue to cook and stir over medium heat until broth is absorbed. Continue adding broth, 1/2 cup at a time, stirring constantly until the broth has been absorbed, but mixture is creamy. (This should take about 25 minutes total.)
Remove from heat; stir in butter or margarine, the 2 tablespoons cheese, and the pepper. Spoon into a serving bowl. Sprinkle with additional finely shredded Parmesan cheese, if desired. Makes 8 to 10 servings.