This decadent Peanut Butter Mousse & Berry Jam Cake is a sophisticated version of the classic PB&J sandwich! The moist white cake is reminiscent of nostalgic white bread, the peanut butter has been enhanced as creamy mousse, and the jelly is a bit more refined as a homemade jam.
1 and 1/2cupsfresh or thawed frozen berries - raspberries, blackberries, blueberriesany berry combination will work
1/4cupwater
White Cake
2 and 1/4cupsall-purpose flour
2teaspoonsbaking powder
1/2teaspoonbaking soda
1/2teaspoonsalt
3/4cupfull fat sour cream, room temperature
3/4cupwhole milk
1cupunsalted butter, room temperature
1 and 1/4cupsgranulated sugar
5largeegg whites, room temperature
1tablespoonvanilla extractclear vanilla extract will keep the cake whiter
Instructions
For the peanut butter mousse
Chill a medium mixing bowl in the freezer for at least 30 minutes before beginning.
Using a handheld mixer, beat the heavy whipping cream on medium speed until medium peaks form - about 4-5 minutes. You will have reached the right consistency when the whipped cream has a peak with a tip that curls over on itself when the beaters are lifted. Set aside in the refrigerator.
In the mixing bowl of a stand mixer fitted with the paddle attachment, combine the cream cheese, peanut butter, and vanilla beat until smooth, about 2 minutes
Add the powdered sugar and mix for 1 minute.
Add the milk and mix until smooth - about 30 seconds.
Using a spatula, gently fold in the prepared whipped cream into the peanut butter mixture and mix until well incorporated. Place the mousse in the refrigerator until ready to assemble the cake.
For the berry jam
In a medium saucepan, bring the fruit and the water to a boil on medium-high heat. Using a wooden spoon, mash and break down the fruit. Let the fruit cook on low heat for about 5 minutes and continue to stir and mash the fruit to let the fruit break down and all of the juices released.
Using a fine-mesh strainer, strain the berry mixture into a small bowl by pressing the fruit solids with the wooden spoon until only the seeds remain. Scrape the underside of the sieve to make sure to get all of the strained fruit.
Place the fruit in the refrigerator until ready to assemble the cake.
For the white cake
Adjust oven rack to middle position and preheat oven to 350o degrees. Butter 2 8-inch square cake pans and line the bottoms with parchment paper. You can use round cake pans as well.
In a medium bowl, sift together the flour, baking powder, baking soda, and salt. Set aside.
In another medium bowl, mix the sour cream and milk. Set aside.
In a stand mixer fitted with paddle attachment, beat the butter and sugar on medium speed until light and fluffy - about 3-4 minutes - scraping the sides of the bowl as needed. Add the egg whites and vanilla extract and beat until combined.
With the mixer on low speed, add a third of the flour mixture and mix until just combined. Add half of the milk mixture - mix until combined. Add 1/3 of the flour mixture - mix until combined. Add the remainder of the milk mixture - mix until combined. Finish adding the remaining flour mixture and mix the final time by hand using the mixer paddle. Do not over mix each of these steps - the less you mix, the lighter and fluffier the cake will be. You will want to mix each step just until all of the ingredients are incorporated.
Divide the batter evenly between the prepared baking pans. Bake for 25-30 minutes until a toothpick inserted in the middle comes out clean.
Let the cakes cool in the baking pans for 15 minutes, then carefully remove from the baking pans and cool completely on a wire rack. If needed, gently run a knife around the edge of the cakes to loosen from the pans.
Assembling the cake
Once the cakes have cooled completely, line the edges of a cake platter with 4 narrow strips of parchment paper.
Using a long serrated knife, cut each cake into 2 even layers. Place one cake layer on the cake platter. Using a spatula, spoon or offset spatula spread about 1/2 cup of the berry jam onto the cake - covering completely and spreading all the way to the edges of the cake layer. Next, spread 1/2 cup of the peanut butter mousse evenly to the edges of the cake. Top with one of the cake layers.
Top the second layer of cake with 3/4 cup of the peanut butter mousse and spread evenly to the edges of the cake. Top with a third layer of cake. Repeat with the jam and mousse and top with the last cake layer. Spread the remaining mousse over the entire cake
Microwave the remaining jam in a bowl until melted and smooth. Transfer to a piping bag and cut a small opening at the tip (or use a Ziploc bag and cut 1 of the corners of the bag). Pipe the jam in straight lines diagonally on the cake. Using a knife, lightly drag through the lines in the opposite direction.
Carefully remove the parchment paper and serve at room temperature. The cake can be stored in the refrigerator for up to 5 days. Leftovers can also be wrapped in plastic wrap and stored in the freezer for up to 3 months. Bring to room temperature before serving.
Notes
Make the mousse and the jam first, or even a day ahead of time if that works better for your schedule. They both keep well in the refrigerator.
When making the cake batter, you will want to go back and forth with adding portions of the milk and flour mixture, ending with flour. This process keeps the batter from getting overmixed and gives you light and fluffy cake.
I used regular vanilla extract in my recipe (the dark stuff), but you could also use clear vanilla extract. It usually is more of a specialty item and I have seen it available in craft stores with all of the baking and decorating supplies.
When assembling the cake, I always recommend lining your serving platter with strips of parchment paper to help keep the platter clean when you are frosting the cake. Keep the strips relatively thin (no more than two inches) so you can easily pull them out from under the cake when you are done.
I keep my cakes in the refrigerator and just bring to room temperature before serving. With this recipe, it makes me feel more comfortable refrigerating it because of the cream cheese in the frosting.