Prune Spice Cake is a name I avoid using because the word "prune" puts so many people off. Unless you enjoy imploring your picky eater to "Just try it, you'll like it," I'd suggest you call it Spice Cake and skip all that nonsense.
2 dip-and-sweep cups (10 ounces) unbleached all-purpose flour
1 cup (7 ounces) sugar
1 1/2 teaspoons baking soda
1/2 teaspoon salt
1 teaspoon cinnamon
1/2 teaspoon nutmeg
1/4 teaspoon cloves
8 tablespoons (4 ounces) unsalted butter, melted
1/4 cup organic* canola oil
3 large eggs
1 cup (4 ounces) finely diced walnuts
* Of course, I use organic everything, but I mention it specifically for the canola oil because canola oil that is not organic is sure to be genetically modified (GMO or GE).