This ridiculously decadent, fluffy peanut butter mousse cake features a fudge brownie layer and silky 4 ingredient peanut butter mousse- all made entirely vegan! No dairy, no eggs, not even gelatin. Topped with a silky chocolate ganache, it’s the ultimate indulgent peanut butter lover’s dessert!

slice of peanut butter mousse cake

Why you’ll be OBSESSED with this Peanut Butter Mousse Cake:

  • It combines the best flavor combo: peanut butter and chocolate. The peanut butter mousse layer and the brownie layer are unmatched. I adore my classic vegan chocolate mousse cake (and it’s adorable mini version!), but I needed to make something for the peanut butter lovers. The peanut butter mousse is fluffy, rich, and soft, with a punchy peanut butter flavor to complement the deeply rich chocolate in the brownie layer.
  • This recipe is shockingly simple. I used to hear “mousse” in a dessert and think this is going to be impossible. And often times, mousse requires gelatin to set. Which, to me, is not only gross, but also finicky to work with. Not this mousse cake. It sets beautifully with just a few simple ingredients (4 to be exact!). All atop a simple recipe- a brownie base layer made just with a bowl and a whisk.
  • You don’t need any eggs nor dairy. Yep, this peanut butter mousse cake is 100% vegan, and you’d absolutely never know.
bitten slice of peanut butter mousse cake

Step-by-step: How to make a brownie peanut butter mousse cake:

For the full written instructions and ingredient measurements, see the bottom of this post in the recipe card. You can also hit the “jump to recipe” button at the top of this post! Here, we’ll go over a brief overview of the steps, along with providing visuals for a better understanding of the recipe.

The brownie layer:

Unlike my classic chocolate mousse cake, which has a layer of chocolate cake, I decided to go with a brownie bottom here. I felt it was a bit easier and more forgiving in that if you don’t achieve a perfect crinkle top, it’s okay. But with a cake, if you get a bit of sinkage on the top, then it affects the rest of the cake’s texture.

So the base layer is just a classic brownie- my favorite vegan brownies recipe baked in a springform pan!

Much like any brownie recipe, you’ll make it like this:

  • Make the fudge sauce: This is just our neutral oil, chocolate, and cocoa powder, mixture together. Adding in the cocoa powder to the hot mixture of chocolate and oil melted together will help bloom the cocoa powder for an even deeper chocolate flavor.
  • Dissolve the sugar: This part is not only crucial for the crinkle top (which sadly, we won’t see underneath the mousse!), but it’s also key for the texture. The more the sugar is dissolved, the more fudgy the brownie will be.
  • Finish the batter: Combine the fudge sauce with the sugar mixture, along with the flour. Whisk just until combined and pour into your prepared pan.
  • Bake: We’re using a springform pan here so that we can easily remove the mousse cake when you’re ready to serve. Because it’s a 9″ pan, it will bake for the same time as a regular square pan- about 30-32 minutes.
brownie layer

Pro tip: You can even make this gluten-free! Simply swap the all-purpose flour for gluten-free 1:1 baking flour. I’ve tested this recipe with King Arthur Measure-for-Measure Gluten-Free Baking Flour. That one is my favorite!

The peanut butter mousse layer:

This is my favorite part, and deceivingly simple. Most people would think that since traditional mousse calls for gelatin, we’d need a gelatin substitute.

Not the case here. I actually gave this peanut butter mousse a slight tangy flavor with thick vegan cream cheese to help hold its base.

Much like my peanut butter icebox cake or my peanut butter pie, we’ll start by whipping the vegan heavy cream. Then adding in the cream cheese and peanut butter, along with the sugar, and mixing again to incorporate.

peanut butter mousse layer

Finishing the cake:

Of course, no peanut butter mousse cake would be complete without a smear of chocolate ganache. We’re using my simple 2-ingredient vegan chocolate ganache, and garnishing with sliced vegan peanut butter cups.

I use the dark chocolate peanut butter cups from Justin’s as they’re dairy-free. Hail Merry and UNREAL also sell vegan-friendly peanut butter cups, I believe.

assembling the peanut butter mousse cake
sliced peanut butter mousse cake

Pro tip: Because this mousse isn’t set with gelatin, it will start to soften at room temperature (or outside in the heat!). So after about 20 minutes of serving, I would pop this back into the fridge if people want more slices.

slice of peanut butter mousse cake

If you make this recipe, please be sure to leave a comment and a rating ⭐️⭐️⭐️⭐️⭐️ below. This helps others to find the recipes! As always, I absolutely love to see your beautiful creations on Instagram and Pinterest, so be sure to tag me there as well!

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slice of peanut butter mousse cake

Decadent Peanut Butter Mousse Cake – Vegan!

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  • Author: Britt Berlin
  • Prep Time: 30
  • Cook Time: 30
  • Total Time: 1 hour
  • Yield: 16 1x
  • Category: Cake
  • Method: Baking
  • Cuisine: American
  • Diet: Dairy-Free, Vegan
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Description

This ridiculously decadent, fluffy peanut butter mousse cake features a fudge brownie layer and silky 4 ingredient peanut butter mousse- all made entirely vegan! No dairy, no eggs, not even gelatin. Topped with a silky chocolate ganache, it’s the ultimate indulgent peanut butter lover’s dessert!

Ingredients

Scale
  • 1 batch fudgy brownies
  • 16 ounces (452 g) vegan cream cheese, room temperature
  • 2 cups (480 mL) vegan heavy cream, chilled
  • 1 cup (120 g) powdered sugar sugar
  • 1 cup (240 g) creamy peanut butter, unsalted
  • 1 tbsp vanilla extract
  • 1/4 tsp sea salt
  • 1 batch vegan chocolate ganache
  • Vegan peanut butter cups, for garnish

Instructions

  1. Prep: Start by preheating the oven to 350F, and greasing a 9″ springform pan with tall walls with cooking oil. Line the pan and the walls of the pan with parchment paper.
  2. Make the brownie batter: Follow the instructions for making the brownie batter. When it comes time to bake, pour the brownie batter into the prepared pan and place into the oven to bake for 30-32 minutes, or until a toothpick comes nearly clean. 
  3. Cool: Remove the brownie layer from the oven and let cool FULLY before making the peanut butter mousse. This will take about 2 hours. There must be no warmth to the touch on the brownie layer.
  4. Make the peanut butter mousse: In a stand mixer with the whisk attachment or large bowl with a hand mixer, cream the vegan heavy cream until you reach semi-stiff peaks. Then add in the vegan cream cheese and cream again until combined. Finally, add in the powdered sugar, peanut butter, vanilla, and sea salt. Cream together again until smooth. Pour the peanut butter pie filling onto the cooled brownie layer in the springform pan, and smooth the top.
  5. Chill: Refrigerate for at least 4 hours, but preferably overnight.
  6. Make the ganache: When ready to serve, prepare a batch of the vegan chocolate ganache. Let the ganache cool so that it’s pourable but there’s very little warmth to the touch. Carefully remove the peanut butter mousse cake from the pan and pour the ganache on top. Spread to the edges of the pan and top with vegan peanut butter cups.
  7. Serve: Slice and enjoy! Store any leftovers in an airtight container and in the fridge for up to 5 days. 

Notes

Gluten free: I recommend using King Arthur Measure-for-Measure Gluten-Free Baking Flour.