Cook potatoes in boiling water until fork tender. Drain.
Bring a large pot of water to the boil.
Add cabbage and blanch it for 5 minutes.
Drain and immediately run with cold water. Drain and set aside.
In a large skillet, heat oil. Add onion and saute until softened.
Add tomatoes and chillies. Cook for 5 minutes, until the tomatoes have softened a bit.
Add cabbage, salt, pepper, cilantro and potatoes.
Stir to combine and cook for a few minutes until potatoes are heated through.