High Altitude Chocolate Peanut Butter Cake

It just so happens that Noel is a fire building, tent erecting, hardcore hiking Scoutmaster. He takes all that manly skill, plus years of our kids conditioning him to be nonreactive to whining, and tries to inspire his suburban troops (all three of them) to try and like being outdoors, even just a little bit. It’s a hard job and I do my best to support him by letting him practice bandaging on me and even signing up to be a merit badge counselor, but the most supportive thing I’ve done thus far was bake up this cake and a loaf of my sourdough bread for their baked goods auction fundraiser. Both creations were in the top three selling items and netted the scouts $150.

High Altitude Chocolate Cake w/ Peanut Butter Cream Cheese Icing

When I set out to make this cake I knew I wanted it to be mouthwateringly delicious, so I started scouring Smitten Kitchen‘s recipe archives. (I may have a bit of a blog crush on Smitten Kitchen . . . ) When I found her chocolate peanut butter cake I knew I’d found what I was looking for. With a few alterations for altitude and some trial and error using natural peanut butter in the glaze this bake sale cash cow was born.

6" and 9"

Of course, I had to make a 6″ cake for myself. It was the only way the larger cake had any chance of making it to the auction. If you have a small family or aren’t planning on sharing the cake, I highly recommend the 6″ cake. Your thighs will thank you. Ultimately, I think the chocolate peanut butter glaze is optional. It adds a nice finishing touch, but the cake would still be delicious without it.

Chocolate Peanut Butter Cake

  • 2 cups all-purpose flour + 3 TBSP
  • 2 1/2 cups sugar (pinch below the cup line)
  • 3/4 cup unsweetened cocoa powder
  • 2 teaspoons baking soda (tiny bit below the top of the spoon)
  • 1 teaspoon salt
  • 1 cup neutral oil, such as canola, soybean or vegetable blend
  • 1 cup sour cream
  • 1 1/2 cups water + 2 TBSP
  • 2 tablespoons distilled white vinegar
  • 1 teaspoon vanilla extract
  • 2 eggs
  1. Preheat the oven to 350 degrees F. Grease and flour the bottoms of three 8″ cake pans or two 9″ cake pans (I have 9″ pans and splitting the batter between the two makes for nice thick cake layers).
  2.  Whisk together the flour, sugar, cocoa powder, baking soda, and salt in a large bowl. (You can also sift them into the bowl, but I skipped that and just tried to whisk some air in and make it a little fluffier.)
  3. Add the oil and sour cream and stir until blended. Gradually add in the water, then the vinegar and vanilla. Whisk in the eggs and beat until well blended. Scrape down the sides of the bowl and be sure the batter is well mixed. Divide among the prepared cake pans.
  4. Bake for 25 to 35 minutes, or until a toothpick inserted in the center comes out almost clean. Let cool in the pans for about 5 minutes and then cover with plastic wrap (this traps in the moisture).  Let cool 10-15 minutes more in the pans, then carefully remove the plastic wrap and lay it on the cooling rack, run a knife around the edges of the cake, and turn the layers out onto the plastic wrap. Put more plastic wrap on the exposed side and allow to cool completely.
  5. Once cooled, transfer the layers to the freezer for at least 30 minutes. This will help them be a little more firm during assembly.

Peanut Butter Frosting
Makes about 5 cups (Which was enough to frost both a 6″ and 9″ cake)

  • 10 ounces cream cheese, at room temperature
  • 1 stick unsalted butter, at room temperature
  • 5 cups powdered sugar
  • 2/3 cup smooth peanut butter
  1.  Beat the cream cheese and butter until light and fluffy. Gradually add the confectioners’ sugar 1 cup at a time, mixing thoroughly after each addition and scraping down the sides of the bowl often. Continue to beat on medium speed until light and fluffy, 3 to 4 minutes.
  2. Add the peanut butter and beat until thoroughly blended.

Chocolate-Peanut Butter Glaze
Makes about 1 1/2 cups

  • 8 ounces semisweet chocolate, coarsely chopped
  • 3 tablespoons smooth peanut butter
  • 2 tablespoons light corn syrup
  • 1/2 cup half-and-half (I needed to add more to thin out my glaze, I think it was due to the type of peanut butter I used)
  1. In the top of a double boiler or in a bowl set over simmering water, combine the chocolate, peanut butter, and corn syrup. Cook, whisking often, until the chocolate is melted and the mixture is smooth. (Alternately, you can do this in the microwave in 30 second bursts stirring in between.)
  2. Remove from the heat and whisk in the half-and-half, beating until smooth. (My mixture was pretty thick and I had to fold my half-and-half in with a spoon in the beginning.) Begin assembling the cake immediately.
  3. Place one layer on a cake stand or large serving plate. Spread 2/3 cup of the Peanut Butter Frosting evenly over the top if using three layers or about 1 C if using two layers. If you have three layers, repeat with the next layer then place the last layer on top and frost the top and sides of the cake with the remaining frosting. (Deb noted, and I second this, that “Making a crumb coat of frosting–a thin layer that binds the dark crumbs to the cake so they don’t show up in the final outer frosting layer–is a great idea for this cake, or any with a dark cake and lighter-colored frosting. Once you ‘mask’ your cake, let it chill for 15 to 30 minutes until firm, then use the remainder of the frosting to create a smooth final coating.”)
  4. To decorate with the Chocolate–Peanut Butter Glaze, simply pour the glaze over the top of the cake, and using an offset spatula, spread it evenly over the top just to the edges so that it runs down the sides of the cake in long drips. My glaze was still sort of thick, even with the thinning, so I had to kind of shape my “drips.”
  5. Refrigerate, uncovered, for at least 30 minutes to allow the glaze and frosting to set completely. Letting it warm up before cutting will help the glaze not crack when cutting into the cake.

Six Inch Variation:

Follow the instructions above using the following amounts. Pour into two 6″ cake pans and reduce baking time to 20-30 minutes.


  • 1 C + 1.5 TBSP flour
  • 1 1/4 C sugar (pinch below line)
  • 1/4 C + 2TBSP cocoa
  • 1 tsp baking soda (tiny bit below line)
  • 1/2 tsp salt
  • 1/2 C oil
  • 1/2 C sour cream
  • 3/4 C +1 TBSP water
  • 1 TBSP vinegar
  • 1/2 tsp vanilla
  • 1 egg


  • 5 ounces cream cheese, at room temperature
  • 1/2 stick unsalted butter, at room temperature
  • 2 1/2 cups powdered sugar
  • 1/3 cup smooth peanut butter

Chocolate Peanut Butter Glaze: 

  • 4 ounces semisweet chocolate, coarsely chopped
  • 1 1/2 tablespoons smooth peanut butter
  • 1 tablespoons light corn syrup
  • 1/4 cup half-and-half (I needed to add more to thin out my glaze, I think it was due to the type of peanut butter I used)
High Altitude Chocolate Peanut Butter Cake

Written by Audrey

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