Heat the butter in a medium saucepan over medium heat. Add the diced apple, honey, cinnamon, ginger, nutmeg, and salt. Sauté for about 3 minutes until the apples begin to soften.
Stir in the oats; then reduce the heat to a simmer. Cook for 5 to 7 minutes, stirring occasionally, until the oats are soft and the mixture thickens. Incorporate the vanilla extract.
Remove the pan from heat and serve immediately with a splash of milk if desired. Top with optional fresh apple slices or other fruit.