In a medium saucepan, combine pineapple, red onion, jalapeños, vinegar, brown sugar, salt, coriander, and ginger. Stir to dissolve sugar.

Bring the mixture to a boil over medium-high heat, then reduce to a simmer. Let cook 15–20 minutes, stirring occasionally, until thickened and syrupy. If using raisins, add them during simmering (< 20 min) to plump up.

Taste and adjust seasoning—add more jalapeños for heat or sugar for sweetness.

Remove from heat. Cool slightly, then scoop into sterilized jars. If canning, process jars according to standard water-bath procedure; otherwise store in airtight containers in the refrigerator for up to 2 weeks.

Use after chilling to allow flavors to meld.