Italian Cream Cake with Mascarpone Buttercream

2 cups (10 ounces) all-purpose flour
3/4 teaspoon baking soda
1/2 teaspoon salt

1 1/2 cups granulated sugar
1/2 cup (4 ounces) butter, at room temperature
1/2 cup canola oil
2 teaspoons pure vanilla extract
4 eggs, room temperature
1 cup buttermilk, at room temperature
1/2 cup heavy cream, cold
1 1/2 cups lightly packed sweetened shredded coconut, plus 1/2 cup for decorating the cake
3/4 cups toasted pecans, chopped, plus 2 cups for finishing and decorating the cake
Mascarpone Buttercream (recipe below)

With rack in center of oven, preheat the oven to 350˚F.  Grease three 8-inch cake pans, line with parchment paper or wax paper, then grease the paper.

Whisk together the flour, soda, and salt in a bowl, making sure the ingredients are well blended.

In the bowl of a stand mixer fitted with the paddle attachment, cream the sugar and butter together on medium-high speed until fluffy, about 4 to 5 minutes, scraping down the bowl frequently.  With the mixer on low speed, drizzle the oil and the vanilla into the mixture and mix until well combined.  Blend in the eggs, one at a time, scraping down the bowl between each addition.

With the mixture on low speed, add the flour mixture in three parts, alternating with the buttermilk in two parts, beginning and ending with the flour.  After each addition, mix until just barely blended and stop and scrape down the bowl.  Stop the mixer before the last of the flour has been incorporated and complete the blending by hand with a rubber spatula to ensure you do not over beat the batter.

In a separate bowl, using either a hand whisk or an electric mixer, beat the heavy cream to soft peaks.  Gently fold the cream into the cake batter, followed by the shredded coconut and the pecans.

Divide the batter evenly between the prepared cake pans and smooth the tops.  Bake until the center springs back when lightly touched, 25 to 30 minutes.  Remove the pans from the oven and run a thin knife around the edges of the pans.  Cool the cakes in their pans on a wire rack for 30 minutes.  Remove from pans and cool completely, top side up.

Bring buttercream to room temperature if made ahead.  Fold in 1 1/2 cups of the remaining chopped pecans

To assemble the cake, lay one layer top side up on a cake platter or flat plate.  Spread the top with approximately one cup of the buttercream.  Place another layer, top side up on the previous layer, again spreading it with one cup of buttercream.  Lay the third layer, bottom side up, and spread with approximately 1 1/2 cups of buttercream.  Cover the sides of the cake with any remaining buttercream.

Sprinkle the cake with the remaining 1/2 cup of pecans, and 1/2 cup of coconut.

Enjoy at once or keep refrigerated.  Bring to room temperature before serving.

Mascarpone Buttercream

5 egg whites
3/4 cup granulated sugar
1/4 teaspoon salt (If using unsalted butter, use 1/2 teaspoon salt)
2 cups butter, diced into tablespoon sized pieces
2 teaspoons pure vanilla extract
3/4 cups (6 ounces) Mascarpone cheese, at room temperature

Combine the egg whites, sugar, and salt together in a bowl.  (Make sure the bowl is very clean and free from any residual fat.)  Bring a pan of water to a gentle simmer.  Place the bowl of egg whites over the simmering water, making sure the bottom of the pan does not come in contact with the water.

Whisk the egg until the sugar has melted, then stir frequently until the egg whites have reach a temperature between 145˚ and 150˚ on an instant read thermometer.

Remove the bowl from the pan and place on a stand mixer.  Using the whisk attachment, beat the whites on medium-high speed until stiff peaks form.  Continue to beat until the whites are completely cool.  Test this by feeling the bottom of the bowl.  It should feel completely cool to the touch.

Turn the mixer down to medium-low and begin adding the butter, a piece at a time.  Once all the butter has been added, scrape down the side of the bowl and whisk for a few more seconds.  Add the Mascarpone cheese and mix until incorporated.

Refrigerate until needed, up to 3 days, or in the freezer for longer storage.

Source:  Mascarpone Buttercream | Sifting Focus