Preheat the oven to 375°F (190°C). Grease a 9-inch tart pan with butter.
In a large bowl, whisk together the flour, sugar, and salt.
Stir in the butter until the mixture forms a crumbly dough.
Add the water and mix until the dough comes together.
Press the dough into the bottom and up the sides of the prepared tart pan.
In a separate bowl, combine the apples, sugar, cinnamon, and nutmeg.
Arrange the apple slices in a circular pattern on top of the tart.
Brush the melted butter over the apples.
Bake for 30 minutes or until the crust is golden and the apples are tender.
Let cool before serving.