- 1 1/3 cups (5 1/3 ounces) sifted cake flour (sift the flour into the measuring cup)
- 3/4 cup all-purpose flour
- 1 1/2 teaspoons baking powder
- 1 teaspoon kosher salt
- 4 ounces (1 stick) unsalted butter, at room temperature
- 2 cups sugar
- 1/3 cup canola oil
- 1 tablespoon vanilla extract
- 4 egg yolks, at room temperature
- 3 whole eggs, at room temperature
- 1/2 cup buttermilk, at room temperature
- 1/2 cup heavy cream, cold
- 6 cups blueberries, fresh or frozen
- 1/2 cup sugar
- 1/4 cup cornstarch
- zest of 1/2 lemon
- 1 pound (about 4 cups) powdered sugar, sifted (sift after measuring)
- 1 cup (2 sticks) unsalted butter, at room temperature
- 1 tablespoon vanilla
- Pinch salt
- Preheat oven to 350°F.
- Butter two 8-inch cake pans and line with buttered parchment.
- Whisk the flours, baking powder and salt together in a bowl.
- In a stand mixer, fitted with a paddle attachment, cream the butter and sugar together on medium speed for about 5 minutes. Scrape down the bowl.
- On low speed slowly add the oil and vanilla until combined.
- Mix in the yolks and whole eggs one at a time, scrape down the bowl after each.
- Add the flour in three parts, alternating with the buttermilk, starting and ending with the flour.
- In a separate bowl whip the heavy cream to medium peaks.
- Fold the cream into the cake batter.
- Divide the batter equally into the cake pans.
- Bake for about 35 to 40 minutes or until a tester comes out clean. Allow to cool on a rack.
To make the blueberry sauce:
- In a sauce pot add the blueberries, sugar, cornstarch and zest.
- Cook over medium heat until the sauce is bubbling and the cornstarch thickens and turns translucent.
- Transfer to a bowl and allow to cool to room temperature.
- This can be made a few days ahead, covered and refrigerated.
- Bring the sauce back to room temperature when adding to the icing
To make the icing:
- In a stand mixer fitted with the paddle attachment cream the butter until smooth.
- Add the powdered sugar, vanilla and salt, mix on low-speed until incorporated.
- Turn up the speed and mix until smooth.
- Add 1/2 cup of the room temperature blueberry sauce to the icing and combine.
- Add 1/2 cup more blueberry sauce and combine.
To assemble the cake:
- Slice each of the cakes in two layers.
- Spread about 1/2 cup of icing over the first layer and slightly build up the edges, which will hold in the blueberry sauce.
- Spread about 1/3 cup of the blueberry sauce over the icing, but not all the way to the edge.
- Repeat with two more layers, then finish with the fourth layer of cake.
- Spread the remaining icing over the outside of the cake.
- It will never be perfectly smooth due to the blueberries.
- Serve at room temperature.