Peel, core and slice apples into medium size wedges.
In a large pan over medium heat, add the butter, apples, sugars and cinnamon to the pan. Cook the apples, stirring occasionally until they become soft all the way through, but still hold their shape and are easily pierced by a fork; about 15-20 minutes.
In a small bowl, mix together 2 tablespoons of water and 1 tablespoon of cornstarch. Add this slurry to the pan of apples and cook, bringing to a boil and stirring until the sauce is uniformly thickened and coats the apples. Remove from heat and serve warm.
Notes
Leftovers can be stored in the fridge in an airtight container for up to 6 days. Cooled apples can be placed in a freezer-safe bag or container and frozen for up to 6 months. Thaw in the fridge or place frozen in a pan with a lid and slowly warm up over low heat.