Add the cherries and pineapple into a small saucepan. (If you’re using frozen cherries, slightly thaw them first.) Cook the fruit over medium heat for about 7 minutes, continuously stirring, chopping, and mashing it with the back of a spoon to break up its skin and release the natural juices.

Remove the fruit from the heat and pick out any remaining large pineapple chunks. (Don’t discard them—they’re delicious mixed into oatmeal, yogurt, or cottage cheese.)

Add chia seeds to the fruit and mix well. Transfer the mixture to a mason jar with a lid and refrigerate overnight. The chia seeds will immediately start to form a gel, hence the jelly-like consistency.

You can store this jam in the fridge for up to 10 days.