- Scrub the potatoes; do not peel. Place the potatoes in a large pan, cover with water and boil, covered, until tender when pierced, about 20 minutes. Drain and place in a serving container. Keep warm.
- Melt butter in a frying pan over medium heat. Add chopped onion and green onions and cook until limp. Add the tomatoes and cook, stirring often, for 5 minutes. Stir in the cream, cilantro, oregano, cumin, and salt and pepper to taste. While stirring, slowly add the cheese and cook until cheese is melted.
- If potatoes are not small, cut them in halves or quarters. Spoom the sauce over the potatoes.
- Serves 4 to 6.