Marinate the meat with vinegar, Vindaloo spice mix, salt, and turmeric for at least half an hour (You can marinate it overnight in a refrigerator). In a electric cooker/slow cooker/crockpot or pot transfer the marinate along with onion oil and combine well. Cook on low heat until the meat is tender. I used my electric cooker and slow cooked beef vindaloo for 3 hours. Serve hot with steamed rice.