Brown Sugar Layer Cake With Cranberry Buttercream

Preparation

1. Step 1

   Heat oven to 350 degrees. Butter three 8-inch cake pans and line the bottoms with parchment paper. Flour the pans and paper.

2. Step 2

   Sift the flour, baking powder and baking soda into a large bowl. Combine the buttermilk and vanilla extract in a small bowl.

3. Step 3

   In the bowl of a stand mixer fitted with the paddle attachment, combine the sugar, butter, oil and salt. Beat on medium-high until very light and fluffy, about 5 minutes. Stop the mixer occasionally and scrape down the bottom and sides of the bowl. Add egg whites one at a time, mixing for about 20 seconds between each egg.

4. Step 4

   Set mixer to low and alternate adding the dry and wet ingredients in three additions. Mix until a few spots of flour remain. Remove the bowl from the mixer. Using a rubber spatula, finish folding in the dry ingredients: Make sure to scrape the bottom and sides of the bowl to ensure the batter is evenly mixed.

5. Step 5

   Divide the batter among the prepared pans (about 2⅔ cups per pan), smooth the tops and tap the pans on a countertop to release any large air bubbles. Bake cakes until golden and puffed, and a tester inserted into the center comes out clean, 25 to 30 minutes.

6. Step 6

   Cool the cakes in the pans on a rack for 10 minutes, then use the tip of a knife to loosen the edges and carefully place them parchment-side down onto the rack to cool completely.

7. Step 7

   Meanwhile, make the cranberry jam: Combine cranberries, sugar, ½ cup water, orange juice and zest, ginger and vanilla in a large saucepan over medium-high heat. Bring the mixture to a boil, stirring occasionally, and cook until the cranberries have burst and juices are thick and jammy, about 5 minutes. Cool mixture to room temperature, then use an immersion blender or food processor to purée the mixture until smooth. Set aside. (You should have about 2½ cups.)

8. Step 8

   Make the buttercream: In the bowl of a stand mixer, combine the egg whites and sugar. Set the bowl over a pot of simmering water and whisk continuously until the sugar has dissolved and mixture is hot to the touch, 5 to 7 minutes.

9. Step 9

   Return the bowl to the stand mixer, and using the whisk attachment, beat the egg white mixture until stiff, glossy peaks form and both mixture and bowl are cool to the touch, about 10 minutes.

10. Step 10

    Switch to the paddle attachment, and reduce the speed to medium. With the mixer running, add the butter a couple of tablespoons at a time and beat the buttercream until smooth and fluffy. During this step, the buttercream will likely break and look curdled: Turn up the speed on the mixer for a few seconds, and it will come back together. Continue until all the butter is incorporated, then add the vanilla and salt. Slowly add ½ cup cooled cranberry jam, and mix until well combined. If the buttercream is extremely soft or runny, refrigerate for about 10 minutes, then whip until smooth.

11. Step 11

    Assemble the cake: If necessary, use a serrated knife to trim the cake layers so they are flat and even. Add a small spoonful of buttercream onto a cardboard cake round or serving plate, and place the first layer of cake, cut side up, on top.

12. Step 12

    Spread about ¾ cup buttercream on top of the cake. Spread about ¼ cup cranberry jam over the buttercream. Be careful not to spread the jam all of the way to the edge so it doesn't spill out the sides. Place the second cake layer on top, and repeat with buttercream and jam. Place the final layer on top, cut side down, and spread the top and sides of the cake with a thin, even layer of buttercream. (Store leftover jam in an airtight container in the refrigerator.)

13. Step 13

    Refrigerate the cake until the buttercream is firm, about 30 minutes. Then spread the remaining buttercream in an even layer over the cake. Serve at room temperature.