Preheat the oven to 350 degrees. Spray an 8” round pan with baking spray and line the bottom with a parchment round.
In a medium bowl, combine the flour, baking soda, salt, and apple pie spice. Set it aside.
In a mixing bowl, beat the butter and sugars for 2-3 minutes or fully mixed and fluffy. Add in the egg and mix. Add in the vanilla and mix again.
Add the dry ingredients into the bowl and mix until fully combined.
Fold in the white chocolate chips and apples. Spread into the prepared pan and bake for 30 minutes or until lightly golden brown and a toothpick inserted comes out clean.
Let it cool in the pan for 15-20 minutes and then move to a wire rack to cool completely.
In a mixing bowl, beat the butter until smooth. Add in the powdered sugar and mix. Add in the apple pie spice, vanilla, and heavy cream and mix. Pipe the frosting around the border of the cake. Drizzle caramel on top. Sprinkle sea salt and serve. I love salty-sweet, so I sprinkle it generously!