This Apple Cider Layer Cake features apple cider flavored yellow cake filled with cooked apples and frosted with apple cider buttercream.
Yield: three layer 8-inch cake
Preheat oven to 350°F. Butter three 8-inch round cake pans. Line bottom with parchment paper. Set aside.
In a medium bowl, whisk together cake flour, kosher salt, baking powder, and baking soda. Set aside. In a large 2 cup measuring glass, whisk together apple cider, milk, and grapeseed oil. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment, cream together butter, sugar, and vanilla until smooth. Scrape down bowl as needed.
With the mixer running on low-medium, add yolks and eggs one at a time. Allowing each yolk/egg to be incorporated before adding the next. Scrape down bowl as needed. Batter may look slightly curdled.
Alternate adding flour mixture and wet mixture. Start by adding 1/4 of flour mixture. Mix on low speed until almost incorporated. Add 1/3 of wet mixture. Once smooth, repeat adding another 1/4 flour mixture followed by 1/3 wet mixture. Start and end with flour mixture.
Scrape down bowl often to ensure thorough mixing. Once all the flour has been added, increase speed to medium-high for 15-20 seconds until batter is smooth.
Evenly divide batter among prepared cake pans. Level using an offset spatula or by using the back of a spoon. Bake for 35-40 minutes until toothpick inserted in center of cake comes out clean. Rotate pans midway through baking.
Allow cakes to cool in pan for 5 minutes. Then, run a mini offset spatula (or knife) along the edges of pan to help loosen cake. Unmold and cool cakes to room temperature on wire rack .
In a small heavy bottomed sauce pot, melt butter over medium heat. Once melted, add chopped apples and lemon juice. Toss to coat apples in butter.
Add brown sugar, salt, and cinnamon. Mix to combine. Add apple cider. Bring mixture to a boil and then reduce to a gentle simmer. Simmer mixture for 5-7 minutes until apples are softened. *Keep in mind, the Granny Smith apples will be a bit firmer than the Gala apples.
In a small bowl, stir together arrowroot powder and 2 teaspoon water. Mix until dissolved. Quickly pour and incorporate into apple mixture. Remove from heat. Transfer to a heat safe container and let mixture cool at room temperature for about 15 minutes.
Beat softened butter in a stand mixer fitted with a paddle attachment until smooth. Add powdered sugar, 2 tablespoons apple cider concentrate, vanilla, and salt. Mix until buttercream is smooth and fluffy. Scrape down bowl as needed to ensure thorough mixing. Add additional tablespoons of apple cider concentrate until desired buttercream consistency is achieved.
In a small bowl, combine apple cider concentrate and Calvados. Set aside.
Fit piping bag with medium round tip. Fill piping bag with about 1/2 cup buttercream. Set aside.
Level cooled cake layers as necessary. Place one cake layer on cake board, serving platter, or cake turntable. Brush or lightly drizzle soaking syrup over cake layer. Spread a thin layer of buttercream on top using a small offset spatula.
Using the filled piping bag, pipe a border of buttercream along the perimeter of the cake round. Pipe another inner circle of buttercream to create a double wall barrier.
Add half of cooled apple filling within buttercream barrier. Place second cake layer on top. Repeat soaking cake, spreading thin layer of buttercream, piping border, and adding apple filling.
Place third cake layer on top. Brush any remaining soaking syrup over cake layer. Spread buttercream around the cake to create a "crumb coat" layer to seal in any crumbs. Chill cake in the fridge for 15-20 minutes to set frosting. If desired, generously coat the chilled cake with additional buttercream for a smooth finish.
Fit a piping bag with a medium star tip. Fill bag with any remaining buttercream. Decorate the top of cake with piped star boarder. Garnish with sprinkles as desired. Store cake in the fridge until ready to serve.
To make apple cider concentrate: Bring 1 cup apple cider to a boil. Reduce to a simmer. Simmer for about 20 minutes until cider has reduced to 1/2 cup. Remove from heat and cool.