Simmer the cherries with the sugar and lemon juice over medium heat for about 8–9 minutes, stirring occasionally, until the mixture becomes bubbly and slightly thickened. If you are using frozen cherries, omit the water.
In a small bowl, whisk the cornstarch with 2 tablespoons of water until smooth. Stir one tablespoon of the warm cherry mixture into the cornstarch slurry, then slowly add it back to the saucepan. Cook, stirring continuously, for about 1 minute, until the cherry pie filling thickens.
Storing: Transfer the cherry filling into jars and allow them to cool completely. Store in the refrigerator for up to 7 days or in the freezer for up to six months.
Serving: Enjoy the cherry pie filling warm or chilled over waffles, French toast, pancakes, ice cream, cheesecake, muffins, chia pudding, pavlova, and similar desserts. It also works well as a pie or tart filling, or as a layered component in creamy desserts like tiramisu or Heaven on Earth cake.
Notes
This recipe yields 700g / 24 ounces of cherry pie filling, which is slightly more than a standard 21oz can. This gives you a little extra to taste while still having enough for your pie recipe. :)
Do not leave out the lemon juice, as it enhances the natural flavor of the cherries.
Adjust the sweetness to taste by increasing or reducing the sugar.
Frozen cherries work just as well as fresh, though they may need a few extra minutes to cook, and the added water can usually be omitted.
For a thicker or looser filling, simply simmer the mixture longer to reduce it further, or remove it from the heat sooner for a softer consistency.
For extra flavor, consider adding a pinch of cinnamon, vanilla extract, or almond extract, which pairs especially well with cherries. A splash of orange juice or a bit of orange zest can add depth, while a small amount of kirsch or brandy brings a more grown-up note.