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This homemade white chocolate cake is covered with a fresh blueberry frosting. The combination of flavors in the Blueberry Pistachio Cake are absolutely perfect. It’s covered with a white chocolate ganache and pistachios.

Blueberry Pistachio Layer Cake

  • Author: Julianne Dell
  • Prep Time: 30 mins
  • Cook Time: 20 mins
  • Total Time: 50 minutes
  • Yield: 8-10 slices

Description

This Blueberry Pistachio Layer cake is a homemade white cake layered with a fresh blueberry frosting and covered with white chocolate ganache and pistachios.

Ingredients

  • For the blueberry syrup:
  • 12oz (340g) blueberries
  • 1 cup granulated sugar
  • 1 cup water
  • For the cake:
  • 6 large egg whites
  • 1 cup (2 sticks) unsalted butter, softened
  • 2 ¼ cups granulated sugar (424 g)
  • 2 teaspoons vanilla extract
  • 1 cup light sour cream
  • ½ cup milk
  • 2 ¾ c flour (340 g)
  • 1 teaspoons seat salt
  • 1 teaspoon baking soda
  • For the frosting:
  • 2 cups (4 sticks) unsalted butter, softened
  • 8 cups powdered sugar
  • 2 tablespoons heavy whipping cream
  • Prepared blueberry sauce
  • For the topping:
  • 1 cup white chocolate chips
  • 3/4 to 1 cup heavy whipping cream
  • ¼ cup pistachios for garnish

Instructions

  1. For the blueberry sauce: Start with the blueberry syrup. In a medium saucepan, combine blueberries, granulated sugar and water. Simmer over medium heat until the sauce is reduced by half, this should take about 20 minutes. Sauce will thicken as it reduces.
  2. Strain the sauce through a fine sieve, using a spatula to push the sauce through the sieve. Place the juice in the refrigerator until it’s completely cool.
  3. For the cake: Preheat the oven to 350°F. Grease three 8-inch pans and line with parchment paper.
  4. Using the metal bowl of your stand mixer with the whisk attachment, whisk the egg whites on medium-high speed until stiff peaks form. Remove whipped eggs whites from the bowl and set aside.
  5. Change to the paddle attachment and combine unsalted butter, granulated sugar and vanilla extract. Cream together for 2-3 minutes until well combined.
  6. Add the sour cream and milk to the mixing bowl and beat at a low speed until all ingredients are well combined, scraping down the bowl as needed.
  7. In a separate bowl, combine the flour, salt and baking soda and stir to combine.
  8. With the mixer on a low speed, slowly add the flour mixture to the bowl and continue mixing until combined, scraping down the bowl as needed.
  9. Using a spatula, fold the egg whites into the batter, turning the batter over gently until the egg white are well combined. This may take a little elbow grease, but do not mix vigorously or you will deflate the egg whites.
  10. Divide the batter evenly between the three cake pans. Bake at 350°F for 18-22 minutes, rotating the cakes in the oven halfway through to ensure even baking. To check for doneness, insert a toothpick into the center of the cake. If the toothpick comes out clean, your cake is done. Allow the cake to cool completely.
  11. For the frosting: Cut the butter into pieces. Using the paddle attachment, whip the butter for 3-4 minutes, scraping down the bowl occasionally. Beat until the butter looks light in color.
  12. Add 4 cups of powdered sugar, one cup at a time and mix on low speed until it’s incorporated into butter. The frosting will start to thicken.
  13. Begin to alternate in the blueberry sauce and heavy whipping cream while alternating in additional cups of powdered sugar until all the powdered sugar, heavy cream and blueberry sauce have been added. Continue beating until all ingredients are combined and then beat it at a high speed for 1 minute to whip some additional air into the frosting.
  14. To build the cake: Even out the top of the cake by cutting off the dome using a serrated knife.
  15. Place a dollop of frosting on the bottom of the cake plate and place the bottom layer of cake on top. The frosting will help prevent the cake from sliding.
  16. In order to create even layers, I use a piping bag fitted with an open round tip, or simply cut off the end of the piping bag. I also highly suggest using a lazy Suzan to rotate the cake as you work.
  17. Fill the first layer of frosting by using your piping bag and pipe from the outside edge into the center. Gently spread the frosting with an offset spatula to fill in the gaps.
  18. Place the next layer of cake on top and repeat the above instructions to fill the layer of frosting.
  19. For the top layer of cake, place it inverted, so the bottom of the cake is actually the top, creating a nice and smooth top edge.
  20. Proceed to add your crumb coat by adding a cup of frosting to the top of the cake and gently spread out to the edges and down the sides. Use the leftover frosting in your piping bags to fill in the cracks between the layers.
  21. Using an offset spatula or icing smoother, wipe away the excess frosting, leaving you just enough to coat the outside of the cake. Do not mix your crumb coating frosting back into your icing if it has cake debris in it. Refrigerate the cake for 15-20 minutes to allow the crumb coat to harden.
  22. Remove the cake from the refrigerator and proceed to add the remaining frosting to the top and edges of the cake. To get a nice smooth edge, use your offset spatula and icing smoother to wipe away excess frosting.
  23. Take the extra frosting and pipe florets on top of the cake.
  24. For the ganache: In a microwave-safe bowl, combine the white chocolate and heavy whipping cream. Microwave at 50 percent power for 30 seconds at a time, and stir after each 30 seconds. Repeat until the chocolate is melted and smooth. The white chocolate ganache should run smoothly off your spoon. Add additional heavy whipping cream if needed to make the ganache thinner.
  25. Drizzle the white chocolate down the sides and over the top of the cake.
  26. Garnish with crushed pistachios.