Let’s dive into the creation of this scrumptious cake. Follow these steps, and soon your kitchen will be filled with the irresistible scent of homemade goodness.

1. Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish with butter or non-stick spray.
2. In a large bowl, cream together the softened butter and granulated sugar until light and fluffy, about 3-4 minutes.
3. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
4. In a separate bowl, whisk together the flour, baking powder, baking soda, and salt. Gradually add the dry ingredients to the butter mixture, alternating with the buttermilk.
5. Gently fold the apple slices into the batter, ensuring they are evenly distributed.
6. Pour the batter into the prepared baking dish, smoothing the top with a spatula.
7. For the crumb topping, combine the brown sugar, flour, and cinnamon in a bowl. Cut in the cold butter using a pastry cutter or your fingers until the mixture resembles coarse crumbs.
8. Sprinkle the crumb mixture evenly over the cake batter.
9. Bake in the preheated oven for 45-50 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool in the pan on a wire rack before slicing.

Baking this cake often brings back memories of my time in Italy, where every ingredient seemed to tell its own story. The simplicity of the steps is meant to reflect the rustic charm of the Italian countryside, where traditions are cherished and flavors respected.