Cook and stir onion, garlic and jalapeno pepper in oil in Dutch oven until onion
Add lamb. Cook and stir over medium-high heat until lamb is light brown,
about 15 minutes; drain fat.
Stir in tomatoes, coriander, cumin, salt, turmeric
and chili powder; break up tomatoes with fork. Heat to boiling; reduce heat. Simmer
uncovered, stirring occasionally, until sauce is thick, about 15 minutes.
Add potatoes, water and vinegar. Heat to boiling; reduce heat. Cover and simmer
Uncover and simmer, stirring occasionally, until lamb and potatoes are
tender and sauce is thickened, 15 to 20 minutes.