1-Peel apples and cut into quarters. Remove cores, roughly chop, and reserve.
2-Heat oil in a large saucepan over high heat.
3-Add mustard seeds, cover and cook until popping stops.
4-Reduce heat and add onion, red bell pepper, and salt.
5-Cook, uncovered, stirring occasionally, until onions are translucent.
6-Stir in garlic, Serrano chilli, ginger, and allspice, and cook an additional minute.
7-Add remaining ingredients, including reserved apples.
8-Cook, uncovered, over moderate heat, until mixture is soft and aromatic, about 40 minutes.
Chill before serving.