In a large wok or large pan or heavy bottomed casserole, heat the vegetable oil and margarine over medium flame. Fry garlic followed by the turmeric. Add in onions and continue frying. Add the bay leaf and half of the cracked pepper and salt.
Add in the chicken pieces and continue sautéing. Cook over medium heat until the chicken renders its own liquid. There is no need to add water. Continue simmering on low heat until the chicken is partially cooked through and liquid is reduced.
Add the vinegar and continue simmering uncovered. When it boils, add the rest of the cracked pepper, adjust the salt level and add the sugar, if using.
Continue simmering on low heat until the chicken is fully cooked through and liquid is again reduced, has slightly thickened and somewhat oily.
Transfer in a serving bowl and serve with lots of steamed rice. This is distinctly delicious and perfect for rice.