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Citrus Mousse Cake with Buttercream Frosting


This tall, tangy lemon cake filled with layers of lime mousse and frosted with white buttercream is just the thing for a birthday, bridal shower, or other especially delicious occasion.

  • Prep:
  • Total Time:
  • Servings: 16
citrus mousse cake with buttercream frosting

Photography: Ngoc Minh Ngo

Source: Martha Stewart Living, May 2017


  • 2 1/2 sticks unsalted butter, room temperature, plus more for pans
  • 3 3/4 cups unbleached all-purpose flour, plus more for pans
  • 3 1/4 teaspoons baking powder
  • 1/4 teaspoon baking soda
  • 2 teaspoons kosher salt
  • 2 1/2 cups sugar
  • 2 teaspoons finely grated lemon zest, plus 1/4 cup fresh juice
  • 5 large eggs, room temperature
  • 1 1/2 cups buttermilk, room temperature
  • Citrus Mousse Filling
  • 4 cups Italian Meringue Buttercream
  • Edible flowers, meringues, confetti candies, and candy pearls, for decorating (optional)


  1. Preheat oven to 325 degrees. Butter two 8-by-2-inch round cake pans. Line with parchment; butter parchment. Dust with flour, tapping out excess.

  2. Whisk together flour, baking powder, baking soda, and salt until thoroughly combined, 30 seconds. Beat butter with sugar and zest until light and fluffy. Beat in eggs, one at a time, thoroughly combining after each addition and scraping down bowl as needed. Beat in lemon juice. With mixer on low, add flour mixture in 3 batches, alternating with buttermilk and beginning and ending with flour.

  3. Divide batter evenly between prepared pans, smoothing tops with an offset spatula. Bake, rotating pans halfway through, until tops spring back when lightly touched and are light golden, about 1 hour, 10 minutes. Transfer pans to wire racks; let cool 10 minutes. Turn out of pans, remove parchment, and let cool completely, about 2 hours. Cakes can be made to this point and refrigerated, well wrapped in plastic, up to 1 day.

  4. Trim tops of cakes flat. Split each cake horizontally into 3 equal layers. Line an 8-inch cake pan with 2 parchment strips, leaving a 3-inch overhang on all sides. Place 1 cake layer in pan, bottom-side down. Spread 1 cup mousse evenly over it; top with a second cake layer. Repeat, spreading 1 cup mousse between each layer. Finish with a cake layer, bottom-side up. Refrigerate, covered in plastic, at least 1 hour and up to overnight.

  5. Turn cake out of pan onto a cake plate. Spread 1 cup buttercream evenly over top and sides to create a crumb coat. Refrigerate 15 minutes. Spread remaining 3 cups buttercream over top and sides. Decorate as desired.


If you prefer the lighter flavor of whipped cream to the buttercream frosting, whip 2 cups heavy cream with 1/4 cup confectioners' sugar and 1 teaspoon pure vanilla extract to stiff peaks, and frost with that.

Reviews Add a comment

  • sirka-sie111ho
    28 MAY, 2017
    As a chef trained in Germany I must say this is how a cake should look like...and it probable tastes wonderful. Thank you
  • MS11947984
    6 MAY, 2017
    I looked upon this recipe as a test of my baking ability, and patience. I did it over 3 days--one for the cakes; one for the lime mousse; and one for icing and decoration. I made it exactly as suggested with one exception--I doubted I could split each cake into 3 layers, so I baked the cake in 3 8x2" pans instead of two, and split each cake in half. That made it slightly taller than the original perhaps, but it was more doable for me. The cake is delicious and extremely impressive--the cake layer is rather dense on its own. I do not know if I will ever do it again because of the complexity, but possibly for a really big occasion. It's a definite winner, and it will definitely use all your skills! Quite beautiful. I even baked tiny meringues as in the photo, and robbed my garden of flowers for decoration. Whew!
  • fareehashah11
    5 MAY, 2017
    wow Amazing !! i like your blog very Good ideas For Birthday cake ,i live in Newyourk and my family lives in pakistan privious moth My Niece Birthday i send birthday cake for My sweet niece , i use online gifting Service
  • cakengiftsindia
    2 MAY, 2017
    Our w[filtered] family would like to thankyou for given this amazing recipe. It was marvelous!!!!!
  • christianemeis
    1 MAY, 2017
    Could y have your recept in French. My email or if magazine exist in French. Thanks for the answer