In a medium saucepan over medium heat, add cherries. Cover and cook, stirring frequently, until the natural juices of the cherries are released and the contents are beginning to simmer (about 10-15 minutes).

In a small mixing bowl, whisk together cornstarch and water until smooth.

Reduce heat to low and pour the cornstarch slurry, sugar, and lemon juice into the simmering cherries. Stir to combine.

Bring the mixture back to a simmer and continue cooking until the mixture has thickened. This happens quickly, about 1-2 minutes.

Remove from heat and allow to cool completely before adding to your favorite dishes or storing. This will make about 3 cups of filling.

Store in the refrigerator for up to 4 days, or freeze for up to 3 months.