In a medium saucepan, combine the bananas, strawberries, peaches, pineapple, brown sugar, lemon juice, and cinnamon.
Bring to a gentle boil over medium heat, stirring often so it doesn’t stick.
Let it simmer for about 25–30 minutes, or until thickened to your liking. Keep stirring—it likes attention.
Remove from heat, then stir in the rum.
Let it cool before transferring to clean jars. Store in the fridge for up to 2 weeks.