Preheat the oven to 375 F.
Mix together the flour, baking soda, cinnamon, nutmeg and salt in the stand of your mixer.
In a separate bowl, mix together the egg, buttermilk, melted butter, vanilla, and brown sugar until sugar has dissolved.
Add the liquid ingredients to the dry.
Dice the apple in a food processor.
Sprinkle the apple into the batter and stir until just blended.
Line and butter a springform pan.
Pour the batter into the pan.