Preheat oven to 350°F (175°C). Grease and line two or three 8-inch round cake pans with parchment paper.

1. In a medium bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, and nutmeg.
2. In a large mixing bowl, cream the butter, granulated sugar, and brown sugar until light and fluffy. Add eggs one at a time, mixing well after each. Stir in vanilla extract.
3. Alternate adding the dry ingredients and buttermilk to the wet mixture, mixing until just combined.
4. Gently fold in chopped apples and optional nuts.
5. Divide batter evenly between prepared pans and smooth the tops. Bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean.
6. Cool cakes in pans for 10 minutes, then transfer to wire racks to cool completely.
7. For the frosting, beat cream cheese and butter until smooth. Add powdered sugar gradually, then mix in vanilla and cinnamon (if using). Beat until fluffy.
8. Once cakes are cool, frost between the layers, then over the top and sides. Decorate with caramel drizzle or chopped nuts if desired.
9. Let cake sit at room temperature for 15–30 minutes before slicing and serving.