While the fruit is cooking down, combine 1T of Jello with 1 1/2 T of cornstarch in a small bowl or ramekin (if not using Jello, use a tablespoon of granulated sugar). Add the Jello and cornstarch mixture to the pan and continue to stir over medium-high heat for another minute or two until thick. Remove from heat and transfer into a bowl. Add lemon, cinnamon and vanilla. Bring to room temperature or refrigerate until ready to use. This is a great step to do ahead of time!