Beat the butter with a mixer at medium speed until fluffy; gradually add the sugar, beating well. Add the eggs, 1 at a time, beating just until blended after each addition. Add the apple, beating just until blended.
Whisk together the flour, baking soda, cinnamon, cloves and salt; add to the butter mixture, and mix just until blended. Stir in the walnuts, if desired.
Pour into a lightly greased 13-by-9-inch baking pan. Bake 30 to 35 minutes or just until a wooden pick inserted into the center comes out clean. Let cool on a wire rack 10 minutes. Serve with Homemade Caramel Sauce and, if desired, whipped cream or ice cream.
Homemade Caramel Sauce:
Cook the sugar, half-and-half, butter, and salt in a small saucepan over medium-low for 5 to 7 minutes, whisking slowly, until thickened. Remove from the heat, and let cool slightly before serving.
Keep refrigerated up to one week after you make it. Just be sure to warm it up before serving.
You can use most any type of apple. Gala or Red Delicious work great too.