Chocolate Peanut Butter Layer Cake with Peanut Brittle

We are going to go waaaaay back and take a look at a cake I made in September for my mom's birthday. I couldn't let this one slip by. It was a moist chocolate cake with creamy peanut butter filling, tangy frosting, and spectacular peanut brittle.

In case you're wondering..the camera connector cord thingy decided to take a vacation...hence the long break between posts.

I got this recipe from one of my favorite cookbooks, A Year in Chocolate by Alice Medrich. I look back on the arrival of the book with fond memories as I received it in the mail the day I got engaged, February 6th, 2010. I thought I was meeting up with Ryan to go car shopping and he was a little late (getting ready to propose, I now know!), so I read it in the car while I was waiting.

Anyway, everything I've made from it has been wonderful. This particular recipe is called Chocolate Peanut Butter Layer Cake.

First, you gotta make the brittle. As a side note, don't let the technicality of this recipe scare you. It's just simple numbers, a good chunk of time, and a little bit of patience.

Peanut Brittle
1/2 cup chopped peanuts
1/2 cup sugar
1/4 cup water
1/8 tsp cream of tartar

Have the nuts, a wooden spoon or silicone spatula, a white plate, a skewer or spoon, a small bowl of water, and a pastry brush or paper towel ready at the side of the stove. Things are going to happen fast! Also spray a foil or parchment lined baking sheet.

In a 3-4 cup saucepan, combine the sugar, water, and cream of tartar. Stir gently (don't whisk, please) over medium heat until most of the sugar looks dissolved. Stop stirring and bring to a simmer. Cover and simmer for 2-3 minutes. Uncover and wash down the insides of the pot with a wet pastry brush or a wet wad of paper towel. Continue to simmer until it begins to color. Swirl the pot instead of stirring if it is coloring unevenly.

Use the skewer or spoon to drop a bead of syrup on the plate. When a drop looks pale amber, add the nuts and turn gently with a wooden spoon or silicone spatula until completely coated. Continue to cook without stirring until a drop of syrup looks reddish amber.

IMMEDIATELY scrape the mixture onto the baking sheet and spread as thin as possible. Let cool and harden. Break into shards or chop. Congratulations! The hardest part is done!

Cake
All ingredients should be at room temp.
1 1/4 cups AP flour
2/3 cup unsweetened Dutch process cocoa powder
3/8 tsp baking powder
3/8 tsp baking soda
1/2 tsp salt
1/2 cup sour cream or plain yogurt
16 tbsp unsalted butter, slightly softened
1 1/4 cups sugar
3 large eggs
1 1/2 tsp vanilla

Prepare two 8 inch round layer cake pans by lining on the bottom with a round of parchment paper and spraying it and the sides with baking spray. Position the rack in the lower third of the oven and preheat it to 350.

Sift the flour, cocoa, baking powder, baking soda, and salt together 3 times. Yes. 3 times. Set aside.

Combine sour cream with 1/4 cup water and set aside.

In a medium to large bowl with an electric mixer, beat the butter for a few seconds until creamy. Add the sugar in a steady stream and continue to beat (at high speed if you have an old school hand mixer like me or medium speed if you have a fancy schmancy stand mixer) until light and fluffy, about 4 minutes.

Next, break the eggs into a small cup, add the vanilla, and whisk to combine. Beat the eggs into the butter mixture gradually, taking 1.5 to 2 minutes, beating constantly.

Stop mixing and add one third of the flour mixture to the bowl. Beat on low speed only until no flour is visible. Stop mixing and add half of the sour cream. Beat only until blended. Repeat with half the remaining flour mixture, then all of the remaining sour cream, then the rest of the flour. Stop mixing each time you add something, then beat on low speed just long enough to incorporate the ingredients.

Divide the batter between the pans and spread evenly. Bake until the cake starts to shrink away from the sides of the pan and a toothpick comes out clean, about 25-30 minutes. Cool the cake in the pan on a rack for 5-10 minutes before attempting the nerve-wracking flip. Then...flip each layer onto a rack and peel off the parchment (glad you put those in there now, aren't ya?). Turn the layers right side up and cool completely.

If you want to do this ahead, you can make the layers, wrap them tightly, and keep at room temp for 1-2 days or frozen for 3 months.

Filling
2/3 cup natural smooth peanut butter
1/4 tsp vanilla
1/3 cup powdered sugar
4 tbsp unsalted butter, slightly softened

Beat the peanut butter, powdered sugar, and butter just until blended and smooth. When the cakes are cool, turn one layer upside down on a platter or on a cardboard circle. Spread the filling evenly over the cake. Top with the second layer, right side up.

Finally, make the frosting.

Frosting
5 oz semisweet chocolate
2/3 sour cream (If you try to get by with a normal 4 oz chocolate bar, this will get really tangy. Don't say I didn't warn you.)

Melt the chocolate in a double boiler (put the chocolate in a small bowl and set in a pan of barely simmering water). Stir frequently until smooth. Or if you're a risk taker, microwave on medium for 2.5-3 minutes, stirring every now and then. Off heat, scrape the sour cream on top of the chocolate and stir just to combine. Use IMMEDIATELY to frost the top and sides of the cake. If it gets too stiff or loses its gloss, set the bowl in a pan of hot water for a few seconds to soften. Decorate the cake with the peanut brittle and keep at room temp. Hopefully it will be eaten without you having to throw it out in 3 days. Or you could do an experiment and freeze it.