500 g beef 
100 ml soy sauce
60 ml vinegar
30 ml sugar
30 ml minced garlic
500 ml water
1/2 an onion
The night before
Cut the beef into thin slices, about 3-5 mm wide if possible. Make sure to cut along the grain. Ideally you want a cut of meat that has a well defined grain.
Combine marinade ingredients in a container and store in the refrigerator.
In the morning
Start cooking rice
Put tapa ingredients in a frying pan and simmer till the water is boiled off (about 45 minutes)
Fry some eggs with a bit of oil, you probably want to start when the water from the Tapa dish is getting low.
When the water is gone, add a bit of oil and fry for a short minute on low heat