Preheat oven to 300°F.
On stovetop, heat one tablespoon of cooking oil in Dutch oven.
Lightly salt steak and sear each side, until it releases from the pan. If the steak does not lift easily, it is not ready to turn. Allow it to sear a little longer.
Remove seared steak from pan.
Melt butter in pan.
Add onion and cook until softened.
Add remaining ingredients, except potatoes, stirring to combine.
Return steak to pot and cover with sauce.
Cover and bake for 2-3 hours. Keep an eye on the liquid level and add a little water as needed.
When done, the steak will easily pull apart.
One hour before serving, remove the steak from the sauce and pull apart into smaller pieces. Then return to the sauce and add diced potatoes. Stir. Continue cooking for one hour, until potatoes are tender.
To serve, top with a dollop of plain yogurt and a sprinkle of chopped cilantro.