Banana Blueberry Smash Cake
Prep time
Cook time
Total time
Our daughter Jessica wanted a healthy birthday cake for her daughter Harper’s first birthday “smash cake.” We found this recipe, tried it, and fell in love with the cake’s delicious flavor. Not as sweet as traditional cakes, but there is plenty of natural sweetness from the fruits.

This is a fairly dense cake and takes a long bake time. The original recipe uses one 9-inch pan with a bake time of 50 to 60 minutes. I used 3 6-inch pans for the perfect size layered “smash cake” with a bake time of about 45 minutes.

Use either regular apple juice concentrate which will result in a slightly sweeter cake; or use unsweetened apple juice for less sweetness. Use very ripe bananas for a stronger banana flavor. Peel and mash bananas just before adding to cake batter to prevent turning brown. You can use either fresh or frozen blueberries. I used frozen berries for this cake which are easily chopped while still frozen. Admittedly the Flour Buttercream I used doesn’t fall into the healthy category, but it goes wonderfully with this cake and pipes beautifully into perfect rosettes.

Jessica created the adorable cake-topper bunting, with the decorations and colors all complementing a “shabby chic” theme. Our Granddaughter Harper loved her birthday cake; we had a fun and beautiful day capturing these memories. The beautiful pictures were taken by our Daughter-in-Law Christie. See more of Christie’s photography at Christie Hickey Photography.
Recipe type: Dessert | Smash Cake
Serves: 8 to 10 servings
Small amount of vegetable shortening and flour for preparing pans
Cake Batter:
  • 1 cup all purpose flour
  • 1¼ cups whole wheat flour
  • 1 teaspoon baking soda
  • 2 teaspoons baking powder
  • ¼ teaspoon salt (optional)
  • 2½ teaspoons ground cinnamon
  • 1 cup ground old fashioned oatsTip: it takes about 1¼ cups oats to produce 1 cup of ground oats. Use a small food grinder or food processor to grind the oats.
  • 4 large eggs
  • ½ cup (1 stick) unsalted butter, melted and cooled
  • ¾ cup apple juice concentrate, thawed and room temperature
  • 2 cups mashed ripe bananas (about 5 to 6 medium)
  • ½ cup blueberries, chopped (use fresh or frozen berries, thawed and drained)
Flour Buttercream: (Makes about 6 cups):
  • 6 tablespoons all-purpose flour
  • 2 cups milk
  • 1 tablespoon pure vanilla extract
  • 2 cups (4 sticks) unsalted butter, room temperature
  • 2 cups granulated sugar
Preheat oven to 350 degrees F. Prepare three 6-inch round pans for a first birthday layered “smash cake” or one 9 inch round layer cake pan if you prefer; lightly grease the pans with shortening and dust with flour. Tip: Use cake strips around the pans to help ensure the cake rises evenly. Make a cake strip with a length of aluminum foil long enough to encircle the pan with a little overlap. Fold the strip lengthwise until it is about 2 inches wide. Wrap the strip around the outside of the pan and secure it with a metal paper clip or tape.
Cake Batter:
  1. In a medium mixing bowl, combine all purpose flour, whole wheat flour, baking soda, baking powder, salt, and cinnamon; sift or whisk together to mix. Add the ground oats and whisk to mix. Set aside.
  2. In a large bowl of an electric mixer, add the eggs and beat on low speed about 1 minute or until blended, and then increase the mixer speed to medium-high and beat 2 to 3 minutes or until the eggs become thick and lemon colored.
  3. Reduce mixer speed to medium, slowly pour the melted butter into the eggs in a slow steady stream, and then beat for 1 minute longer. Scrape down the sides and bottom of the bowl with a rubber spatula so the mixture blends evenly.
  4. With the mixer on low speed, add about one third of the flour mixture, mix just until the flour is almost completely blended. Scrape the bowl down, and add about one half of the apple juice, blending just until mixed. Scrape the bowl down again and continue alternating with the flour mixture and apple juice, ending with the last portion of the flour, and stirring just until blended.
  5. Remove the bowl from the mixer. Using a balloon type whisk or large rubber spatula, fold in the mashed bananas and blueberries. Tip: Peel and mash bananas just before adding to cake batter to prevent bananas from turning brown.
  6. Bake: Spoon the batter into the prepared pans and smooth the surface with the back of a large spoon or small offset spatula. Bake 40 to 50 minutes for 6-inch pans or 50 to 60 minutes for a 9-inch pan, or until a long toothpick, wooden skewer, or cake tester inserted in the center comes out clean. Remove from oven and place pans on a wire cooling rack to cool for 10 to 15 minutes then remove cake from the pans and place the cake on the wire cooling rack to finish cooling before frosting.
Flour Buttercream:
  1. In a medium heavy saucepan, add the flour, and using a wire whisk, slowly whisk in the milk, whisking until the sauce is smooth and free of lumps. Place the pan over medium heat and cook, whisking constantly, until the sauce comes to a boil and thickens, 5 to 10 minutes. Boil and whisk for 1 minute. Remove from the heat, and set aside to cool to room temperature, or a tepid temperature. While cooling, whisk frequently to keep the sauce smooth. Add the vanilla to the cooled mixture and stir until thoroughly combined. Tip: If the sauce is too warm when added to the creamed butter mixture it will melt the butter. If the sauce is too cold it will not blend smoothly.
  2. Meanwhile, prepare the butter and sugar when the sauce is almost cooled to the right temperature; in a large bowl of an electric mixer, cream the butter and sugar until light and fluffy. Tip: To cream, start by placing the butter in the bowl, with an electric mixer on medium speed begin by beating the butter about 1 minute until it is smooth and light in color.
  3. With the mixer still on medium speed, slowly add the sugar to the butter, either one tablespoon at a time, or in a very slow steady stream, taking about 3 minutes to add all of the sugar, and beating until the butter and sugar are fully incorporated and the mixture is a light, or pale yellow color, with a fluffy texture. While adding the sugar, stop the mixer occasionally to scrape the mixture off the paddle and scrape down the sides and bottom of the bowl with a rubber spatula so the mixture blends evenly.
  4. Gradually add the cooled sauce, adding 2 to 3 tablespoons at a time, beating about 20 seconds between each addition, and then continue to beat for another 1 to 2 minutes to thoroughly blend and the frosting is somewhat fluffy.
  5. The frosting should be used immediately, or refrigerate until needed.
  6. Assembly: The cake shown in the photo was layered and filled with a little of the Vanilla Buttercream Frosting, then crumb coated with the same frosting. Then piped in shades of dusty rose pink for the ombre effect.
  7. Place one of the cake layers on a cake plate. Using an offset spatula spread a small amount of the Vanilla Buttercream Frosting on top. Repeat with another layer of cake, and then place the last cake layer on top with the bottom side up to create a flat top.
  8. Crumb coat the cake by covering the sides and top of the cake with a thin layer of buttercream. Refrigerate the cake until the crumb coat is dried to the touch, about 20-30 minutes. Tip: the crumb coat is a thin layer. Don’t worry if the cake shows through in places, it will be covered again with the final layer of frosting.
  9. When the crumb coat is set, cover the sides and top of the cake with the remaining buttercream. Tip: for the ombre effect, I divided the remaining buttercream into 4 portions. Using dusty rose food coloring I tinted one portion the darkest shade for the bottom row, the second portion a paler shade for the next row, the third portion a still paler shade for the next row, and left the fourth portion with no added food coloring for the top of the cake. I used a size 1M decorating tip to pipe the rosettes.
  10. Banana Blueberry Smash Cake
  11. Harper's Smash Cake Day
Cake Recipe Adapted From:
Recipe Notes
Pan: Three 6” Cake Pan Prep: Greased and Parchment Lined Oven Temp: 350° Storage: Cover and refrigerate

Help: Help: Cake Hints and Tips

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