In a covered large saucepan cook squash over medium heat in a small amount of boiling water about 10 minutes or until just tender. Drain and remove from pan; set aside.
In the same saucepan, cook mushrooms and onion in hot oil until tender. Stir in rice. Cook and stir for 5 minutes.
In another saucepan bring water, bouillon granules, and hot pepper sauce to boiling. Reduce heat and simmer. Slowly add 1 cup of the bouillon mixture to the rice mixture, stirring constantly. Continue to cook and stir until liquid is absorbed. Add 1-1/2 cups more bouillon mixture, 1/2 cup at a time, stirring constantly until the broth has been absorbed. (This should take about 15 minutes.)
Stir squash and remaining bouillon mixture into rice mixture. Cook and stir gently until rice is slightly creamy and just tender. Stir in cheese. Spoon into serving bowl. Makes 6 side-dish servings.