In a large saucepan over medium heat, melt the butter. Add the sliced apples, sugar, cinnamon, nutmeg, and water. Stir well and cover.
Cook for about 6-8 minutes until the apples are slightly softened.
Mix cornstarch with 2 tablespoons of water to create a slurry. Pour this into the saucepan with apples. Stir continuously until the mixture thickens, about 1-2 minutes. Remove from heat and let cool.