Once the cake is baked, remove it from the oven and allow it to cool in the pan for 10 minutes. Then, carefully invert the cake onto a wire rack to cool completely.
In a medium-sized bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, ground cinnamon, and ground nutmeg. Set this mixture aside for later use.
Begin by preheating your oven to 350°F (175°C). Grease and flour a 10-inch Bundt pan to ensure the cake doesn't stick.
Once the butter and sugar are creamed together, beat in the eggs one at a time, ensuring each egg is fully incorporated before adding the next.
In a large mixing bowl, cream together the softened unsalted butter and granulated sugar until the mixture becomes light and fluffy. This step is crucial for achieving a moist and tender cake.
Gently fold in the diced apples and chopped nuts (if using) until they are evenly distributed throughout the batter.
Gradually add the dry ingredients to the wet ingredients in the large mixing bowl. Mix until just combined, being careful not to overmix the batter, as this can result in a dense cake.
lace the Bundt pan in the preheated oven and bake for 50-60 minutes, or until a toothpick inserted into the center of the cake comes out clean.
Pour the batter into the prepared Bundt pan, spreading it out evenly with a spatula to ensure even baking.