In large saucepan over medium heat, melt 3 tablespoons of butter with olive oil. Add onion and cook stirring occasionally until tender and golden about 7 minutes. Add squash and 1/4 broth. Cover and cook over low heat for 10 minutes. Raise heat to medium, add rice and cook for 2 minutes. Add 1/2 cup of broth and cook until liquid has just about evaporated. Continue to add 1/2 cup of broth and stir for 20 minutes. Add remaining butter and cheese. Serve.