Combine cherries and their accumulated juices, almond extract, and granulated sugar in a medium sauce pot. If you use tapioca flour, add it with all the other ingredients and cook them over low heat until cherries release juices.

Cook slowly over low heat until the cherries release all their juices. If you are using canned cherries, I recommend boiling the mixture for 5-10 minutes to evaporate some of the additional water, just be careful that it doesn’t burn.

In a small bowl, whisk together cornstarch and cold water. Reduce the heat to low and slowly pour the cornstarch slurry into the cherry filling while stirring constantly. Turn up the heat and boil the mixture for one minute to begin activating the tapioca or cornstarch.

Pour the mixture onto a parchment-lined rimmed baking sheet or pan and cool completely at room temperature. The pie filling is now ready to use, or you can transfer it to a clean, airtight container and refrigerate for up to 2 weeks or freeze for 3 months.