Creating this cake is as much about tradition as it is about flavor. Let me guide you through each step, just as Mama Lou guided me when I was a little girl watching her bake.

1. Preheat your oven to 350°F (175°C). Grease a 9×13 inch baking pan and set aside.
2. In a medium bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg, and salt. Set aside.
3. In a large bowl, cream the butter and sugar together until light and fluffy, about 3-4 minutes. This step is crucial as it sets the foundation for a tender crumb.
4. Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
5. Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk. Begin and end with the dry ingredients. This method ensures even mixing and a smooth batter.
6. Gently fold in the diced apples (and nuts, if using) until evenly distributed.
7. Pour the batter into the prepared baking pan, spreading it evenly with a spatula.
8. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean. The kitchen will smell divine by now, and your cake should have a lovely golden hue.
9. Allow the cake to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.

As you bake, remember that each step is an opportunity to create memories, just as I did with Mama Lou and Ouma.