Pour cold water into a small bowl with the cornstarch. Whisk until no lumps remain. Set aside
Peel, core and chop apples ¼" cubes.
Place apples, brown sugar, butter, salt and cinnamon in a saucepan. Begin heating over medium heat.
Continue to heat until sugar melts and mixture comes to a low boil.
Whisk the cornstarch/water mixture one more time and pour into the saucepan, stirring constantly.
Continue to heat on medium heat until the apples softened and the mixture thickens (approximately 5 minutes). Stir often.
Remove from heat and transfer to a storage container. Allow to cool to room temperature, place a lid on the storage container and place in the refrigerator.