I found a chocolate peanut butter cake recipe, done by a number of bloggers, but originally from a book called Sky High: Irresistable Triple-Layer Cakes. The frosting called for cream cheese blended with peanut butter, which was not what I was into.
So I invented my own peanut butter filling as I went along, adding what seemed right as the hand blended whirled and grunted and eventually whirled some more: about a cup of peanut butter (the processed stuff, not the natural kind), a lot of powdered sugar, maybe 3 or 4 cups, a half cup or so of simmering water to smooth it out, a teaspoon or two of vanilla extract, and at the end, a sprinkle of sea salt, folded in.
I used the peanut butter filling on top of each cake layer, as well as around the outer surface. Then I put the whole thing in the freezer for a half hour while I made ganache. When the ganache was still warm but not too hot to melt the peanut butter, I covered the entire cake in it, smoothing the sides and top to form a deliciously soft chocolate shell.
The chocolate cake layers, however, are from the recipe, and they are dynamite. The cake is moist as if it has been soaked in some delicious and sweet liquid, even though it has just come straight from the oven. Here's my slightly modified version.
Chocolate Sour Cream Cake
Makes three 8-inch rounds, which when filled and stacked, makes 16 generous slices.
2 cups all-purpose flour
1/2 cup plus 3 Tablespoons unsweetened cocoa powder
2 teaspoons baking soda
1 teaspoon table salt
2 1/2 cups sugar
1 cup canola oil
1 cup low-fat sour cream
1 1/2 cups cold water
1 teaspoon vanilla extract
2 Tablespoons distilled white vinegar
2 eggs at room temperature
Preheat oven to 350 F.
Butter and line with buttered parchment paper three 8-inch round cake pans.
Sift together first four ingredients into a large bowl. Add the sugar and blend with a whisk.
Using a whisk (but not whipping) stir in the oil, then sour cream, then water. When smooth, add the vanilla extract and stir. If you are going to lick the batter, do so now before adding the vinegar. Add the vinegar and stir. Crack two eggs into a separate bowl (or the measuring cup used for the water and oil) and lightly beat the eggs, which should then be added to the batter. Blend until very smooth. The batter will be very runny.
Divide the cake batter evenly into the prepared pans, about 2 cups of batter per pan.
Place on middle rack of oven and bake for about 22-28 minutes. When done, the top of the cakes will have small air bubbles, but the parchment will have begun to slightly pull away from the sides of the pan. Let cool in the pans for about 10 minutes, then invert onto wax paper (the cakes may be too moist to invert directly onto a wire rack, unless you don't mind leaving half your cake behind).
If filling and stacking, freeze cake layers for one hour before handling.