1. Preheat your oven to 350°F (175°C). Grease and flour a 9×13-inch baking pan.
2. In a medium bowl, whisk together the flour, baking soda, cinnamon, and salt. Set aside.
3. In a large bowl, cream together the butter, granulated sugar, and brown sugar until light and fluffy, about 3-4 minutes.
4. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
5. Alternate adding the flour mixture and buttermilk to the butter mixture, beginning and ending with the flour. Mix just until combined.
6. Gently fold in the chopped apples and walnuts, being careful not to over-mix.
7. Pour the batter into the prepared baking pan and smooth the top with a spatula.
8. Bake for 35-40 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool completely before frosting.
9. For the frosting, beat together the cream cheese and butter until smooth. Gradually add the powdered sugar, mixing until well combined. Stir in the vanilla extract.
10. Spread the cream cheese frosting evenly over the cooled cake. Slice and serve with a smile, knowing you’ve created something wonderful from scratch.

Just like when I rolled out tortillas with my abuela, patience is key here. Letting the cake cool ensures the frosting spreads smoothly, creating a beautiful finish.