Preheat the oven to 350°F (175°C) and prepare the Bundt pan.

In a large bowl, whisk together the flour, baking powder, baking soda, salt, cinnamon, and nutmeg.

In another bowl, cream the softened butter, granulated sugar, and brown sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

Stir in the buttermilk until just combined.

Gradually add the dry ingredients to the wet mixture, stirring until just combined.

Fold in the diced apples and nuts if using.

Pour the batter into the prepared Bundt pan, smoothing the top.

Bake for 50–60 minutes or until a toothpick inserted comes out clean.

Allow the cake to cool in the pan for 10 minutes before inverting onto a wire rack.

Once cooled, drizzle with your favorite glaze or serve plain.