Preheat oven to 350?F. Grease a 9-inch round cake pan.
Prepare the apple layer. In a small bowl, mix butter and brown sugar. Spread sugar mixture evenly in greased cake pan. Fan apple slices in two concentric circles on top of the sugar mixture.
Prepare the cake layer. In a medium bowl, mix the flour, cinnamon, cardamom, ginger, cloves, baking soda, and salt. Mix thoroughly with a fork and set aside. In another large bowl, cream the butter and sugar; stir in sour cream, eggs, and vanilla extract. Mix until smooth. Slowly mix in the flour mixture and then the walnuts. Pour batter on top of apples in the prepared pan and spread evenly.
Bake at 350?F for 35-40 minutes or a toothpick inserted in the center of the cake comes out clean. Cool for 5 minutes or until the cake comes away from the edges of the pan, then run a knife around the outside of the pan, and immediately invert on a serving platter, and cut into wedges. Makes 12 servings.