1
Sprinkle strips of sirloin with garlic powder to taste.
2
In a large skillet over medium heat, heat the vegetable oil and brown the seasoned beef strips. Transfer to a slow cooker.
3
Mix bouillon cube with hot water until dissolved, then mix in cornstarch until dissolved.
4
Pour into the slow cooker with meat. Stir in onion, green peppers, stewed tomatoes, soy sauce, sugar, and salt.
5
Cover, and cook on High for 3 to 4 hours, or on Low for 6 to 8 hours.