In a medium saucepan over medium-high heat, add the butter and heat until melted. Add the brown sugar, cinnamon, and sea salt and stir until combined and everything begins to bubble a bit, about 2-3 minutes.
Add apples, tossing everything together until apples are well coated and cook for 5-6 minutes or until apples are tender, stirring occasionally. Remove from heat and serve immediately. NOTE: Sauce should thicken and become "caramelized" within this time without burning.
To serve (hot or cold), add oats to a bowl or mason jar and top it with the caramelized apples, your favorite nuts, and Cocowhip, if desired.