Preheat your oven to 350°F (175°C). Spray a 9-inch round baking pan with non-stick spray or lightly grease with butter.

In a large mixing bowl, beat together softened butter, granulated sugar, and dark brown sugar until light and fluffy, about 2-3 minutes.

Add eggs one at a time, beating well after each addition. Stir in vanilla extract.

In a separate bowl, whisk together flour, baking soda, ground cinnamon, and salt.

Gradually add the dry ingredients to the butter-sugar mixture, mixing on low speed until just combined.

Gently fold in chopped apples and walnuts.

Pour the batter into the prepared baking pan and spread evenly.

Bake in the preheated oven for 40-45 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for 10-15 minutes, then transfer to a wire rack to cool completely.

Slice the cooled cake into wedges and serve. For a special touch, enjoy with a scoop of vanilla ice cream or a drizzle of caramel sauce.