In a large pot over medium heat, combine the cherries, sugar, ¼ cup water, cornstarch, lemon juice, and salt. Stir frequently to mix all the ingredients well, and bring the mixture to a low boil.
Continue cooking for 10 to 15 minutes, until the cherries have softened and the mixture has thickened. Keep an eye on the pot and stir regularly to prevent sticking.
If the mixture looks too thick, add more water a little at a time until you achieve your desired consistency. It should be thick enough to hold together but still pourable.
Once the filling is thick and the cherries are soft, remove the pot from the heat. Stir in the vanilla extract and almond extract.
Let the filling cool before using. If you're not using it right away, transfer it to a container and store it in the refrigerator.
