01 - Preheat oven to 350°F. Grease and flour a 9-inch round cake pan, ensuring thorough coating to prevent sticking.
02 - In a large mixing bowl, whisk together flour, granulated sugar, baking powder, baking soda, salt, and ground cinnamon until uniformly blended.
03 - Beat softened butter in a separate bowl until creamy and light. Add eggs one at a time, mixing thoroughly after each addition to fully incorporate.
04 - Stir buttermilk, vanilla extract, apple cider vinegar, and orange zest into the butter mixture until smooth and well combined.
05 - Gradually pour the wet ingredients into the dry ingredients, mixing gently with a spatula until just combined. Avoid overmixing to prevent tough texture.
06 - Gently fold golden raisins and chopped walnuts into the batter using a rubber spatula, distributing evenly throughout.
07 - Pour batter into the prepared cake pan and smooth the top with an offset spatula for even baking.
08 - Bake for 40 to 45 minutes until a toothpick inserted into the center emerges clean or with just a few moist crumbs.
09 - Allow cake to cool in the pan for 10 minutes before carefully turning out onto a wire rack to cool completely.
10 - Serve plain, dust with powdered sugar for presentation, or accompany with whipped cream for added richness.