In a skillet, melt butter; add beef strips and sprinkle with garlic powder. Sauté, stirring occasionally, until browned.
Remove meat from skillet; add onion and green bell pepper and sauté for 2 minutes. Return meat to the skillet along with tomatoes and bouillon cube. Cover and simmer for 5 minutes if using the sirloin tip cut, 15 to 20 minutes if using round steak.
Blend together the cornstarch, water, soy sauce, sugar, and salt. Add to meat mixture and cook, stirring constantly, until thickened. Reduce heat and cook for 2 minutes longer.
Meanwhile, prepare noodles. Cook noodles according to package directions; drain.
Toss hot pasta with the shredded Cheddar cheese. Serve pepper steak with the Cheddar noodles.
Calories per serving: 430