Trim any fat from round steak and slice meat into thin 5-8cm long strips. Remove the seeds and core from the green capsicum, and slice into thin strips.
In a large frying pan over medium to high heat add oil and cook meat until medium rare, add capsicum and continue cooking until meat is browned.
Reduce heat to simmer and add tomatoes, soy sauce, garlic powder, black pepper and ginger. Cover and simmer 10 minutes.
Dissolve stock cube and cornflour in 2 cups (500ml) water and stir well before adding to simmering beef. Cover and simmer 10 minutes, stirring occasionally, until sauce resembles the consistency of gravy. Remove from heat and serve over a bed of rice.
To cook rice: In a saucepan, bring 2 cups of water to a boil. Stir in 1 cup of rice. Cover and reduce heat to a simmer. Simmer for 20 minutes.