Year 2 begins: Chocolate Peanut Butter Marble Cake

My pals at work and those who follow my blog probably know that chocolate and peanut butter are a regular theme.  It's my favorite combo, as well as Brett Jr's favorite.  Today's project combines them simply and beautifully.  Just look at how pretty this cake is!

On its way into the oven

Fresh out of the oven

Frosted and covered with mini Reese's peanut butter cups

Right before we devoured it

Lessons learned and recipe thoughts:

1. Brett Jr's review: "Is it my birthday? I love this cake!"

2. Taken from one of my favorite baking cookbooks (The Cake Mix Doctor Returns), this is one easy cake.

3. While it may feel intimidating to make a stove-top frosting, this is a really, really easy frosting.  If you can melt butter and stir, you can make it!  And it is seriously delicious - would be great on pretty much anything (including a spoon; not that I ate it with a spoon...really, I didn't).

Chocolate Peanut Butter Marble Cake

1 package (18.25 oz) plain yellow or vanilla cake mix
1/3 cup smooth peanut butter
1/2 cup vegetable oil
3 large eggs
1 tsp vanilla
1 1/3 cups water
1/4 cup unsweetened cocoa powder
2 tbls powdered sugar
2 tbls butter, melted
2 tbls warm water

1. Place a rack in the center of the oven and preheat to 350. Lightly mist a 13x9 pan with cooking spray and dust with flour. Shake out excess flour.

2. Place the cake mix, peanut butter, oil, eggs, vanilla, and 1 1/3 cups water in large mixing bowl and beat with an electric mixer on low speed til blended, 30 seconds. Stop the machine and scrape down the bowl with a rubber spatula. Increase mixer speed to medium and beat for 2 minutes longer, scraping down the side of the bowl again if needed.  The batter should be well blended.

3. Measure out 1 1/2 cups of the cake batter and place it in a medium-sized bowl (note: I measured and left it in a 4-cup pyrex measuring cup that had plenty of room for the remaining ingredients). Set the bowl aside. Pour the remaining batter into the prepared cake pan, smoothing the top with the rubber spatula.

4. Make the chocolate marble by stirring the cocoa powder, powdered sugar, butter, and 2 tbls warm water into the reserved 1 1/2 cups of cake batter until well combined.  Spoon tablespoon-size dollops of this mixture on top of the peanut butter batter. Swirl with a knife to marble the cake, but be careful not to touch the bottom of the pan. Place the pan in the oven.

5. Bake til the top springs back when lightly pressed with a finger, 30-35 minutes. Transfer the cake pan to a wire rack and let the cake cool while you make the Chocolate Pan Frosting (10-15 minutes).

6. Pour the warm frosting over the cake, spreading it with a spatula so it reaches the edges of the cake. Work quickly because the frosting goes on best while still warm. Let set for 15 minutes, then slice and serve the cake.

Chocolate Pan Frosting

8 tbls butter (1 stick)
4 tbls unsweetened cocoa powder
1/3 cup milk
 3-3 1/2 cups powdered sugar, sifted

1. Melt the butter in a medium-sized saucepan over low heat, 2-3 minutes. Stir in the cocoa powder and milk. Cook, stirring, until the mixture thickens and just begins to come to a boil, 1 minute longer. Remove the pan from the heat. Stir in 3 cups powdered sugar, adding more if needed, until the frosting is thickened and smooth and the consistency of hot fudge sauce.

2. Ladle the warm frosting over top of the cake, then spread to the sides. Frosting will harden as it cools.