Wash, dry, peel and core the apples.
Cut into ¼” thick slices or dice into ½-inch cubes.
Place a large non-stick pan over medium heat.
Once the pan is hot add butter and allow it to melt.
Add in the apples. Cook, stirring occasionally until the apples soften. This should take about 6 to 7 minutes: the apples will go from creamy-white to translucent in appearance and should easily be pierced with a fork.
While the apples cook: In a separate bowl, whisk together the cold water and cornstarch until a slurry forms and the lumps are gone.
Add cornstarch slurry to the skillet and gently stir to combine. Bring to a gentle bubble for one minute.
Stir in sugar, cinnamon, vanilla, nutmeg, and a dash of salt. Stir thoroughly.
Remove from heat and serve warm. The sauteed apples will thicken as they stand.