Melt butter in a deep skillet over medium-high heat.
Add apples, cinnamon and sugar and stir until well coated in sugar mixture,. Bring mixture to a simmer. Reduce heat to medium-low and cook, covered until apples are very tender, about 20 minutes.
Whisk together cold water and cornstarch until dissolved. Stir cornstarch mixture into apple mixture and return to a simmer. Cook until thickened, about 2 minutes; remove from heat.
