1.Blend or process chopped onion, garlic, spices, chilli, seeds, ginger and vinegar to a smooth paste.
2.Trim excess fat from pork; cut into 3cm pieces. Combine pork with a quarter of the curry paste in medium bowl; stir to coat pork all over. Cover; refrigerate 3 hours or overnight. Reserve remaining curry paste.
3.Heat oil in large saucepan; cook sliced onion, stirring, until just soft. Add reserved curry paste; cook, stirring, over low heat 5 minutes. Add pork; cook, stirring, about 5 minutes or until pork changes colour. Stir in tamarind paste and tomato; bring to a boil. Simmer, covered, about 40 minutes or until pork is tender and cooked through.
4.Meanwhile, cook rice in large saucepan of boiling water, uncovered, until just tender; drain.
5.Serve curry on rice.
Vindaloo curry paste can be made up to a week ahead and kept, covered tightly, in the refrigerator. Making this dish a day ahead helps intensify the flavours.Note