01 - Preheat your oven to 350°F. Thoroughly grease and flour a 9-inch round cake pan, or line it with parchment paper for easier release.
02 - In a medium mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, ground cinnamon, and ground nutmeg until well combined. Set this mixture aside.
03 - In a large bowl, using an electric mixer or whisk, cream together the softened unsalted butter and granulated sugar until the mixture is light, fluffy, and pale in color.
04 - Beat in the large eggs one at a time, ensuring each is fully incorporated before adding the next. Stir in the vanilla extract and fresh orange zest.
05 - Gradually add the dry ingredients mixture and buttermilk to the butter mixture, alternating between them. Begin and end with the dry ingredients, mixing only until just combined to avoid overmixing.
06 - Gently fold in the mixed dried fruits and optional chopped walnuts or pecans until they are evenly distributed throughout the batter.
07 - Pour the prepared batter into your greased and floured 9-inch cake pan. Use a spatula to smooth the top surface of the batter.
08 - Bake for 45–50 minutes, or until a wooden toothpick inserted into the center of the cake comes out clean, indicating it is fully cooked.
09 - Allow the cake to cool in the pan for 10 minutes. Afterward, invert it onto a wire rack to cool completely before further handling.
10 - Before serving, you may dust the cooled cake with powdered sugar for an elegant finish.