Cook fettuccine according to package directions, adding oil and bouillon granules to water; drain and keep warm.
Melt butter in a large skillet; add green onions, and sauté until tender. Add cheese; reduce heat, and cook, stirring constantly, 5 minutes or until melted. Remove from heat; stir in sour cream, pepper, and garlic powder. Add fettuccine, tossing to coat; serve immediately.