Yellow Birthday Cake with Fluffy Chocolate Ganache Frosting
Flour
Makes one 8-inch layer cake (serves 8-12)

I’m giving you the (very wordy) recipe as written in the book.  A couple of tips.  The cake cools completely in the pans, presumably because it is large and thick, so be sure to grease them well and use a parchment round in the bottom of the pan.  I always refrigerate my cakes with a crumb coating for about 30-60 minutes, but I think the frosting hardened up too much during the waiting time.  So be sure to follow her advice and just frost the cake right after the crumb coating.  She recommends using non-fat buttermilk but I can never find that so I just used low fat.

1½ cups (3 sticks) unsalted butter, room temperature
2 cups granulated sugar
3 eggs
3 egg yolks
1 tsp. vanilla extract
3 cups cake flour
1 tsp. baking powder
½ tsp. baking soda
½ tsp. kosher salt
1 cup buttermilk

Fluffy Chocolate Ganache Frosting
12 ounces semisweet chocolate, finely chopped
1 cup heavy cream
1 cup (2 sticks) unsalted butter, at room temperature
1 cup confectioners’ sugar
¼ tsp. kosher salt
½ tsp. vanilla extract

Position a rack in the center of the oven and heat the oven to 350ºF.  Butter and flour two 8-inch round cake pans.  (DT:  Don’t forget the parchment here!)

Using a stand mixer fitted with the paddle attachment (or a handheld mixer), cream together the butter and granulated sugar on medium speed for 3 to 4 minutes, or until light and fluffy.  (This step will take 8 to 10 minutes if using a handheld mixer.)  Stop the mixer a few times  and use a rubber spatula to scrape the sides and bottom of the bowl and the paddle to release any clinging butter or sugar.

In a small bowl, whisk together the eggs, egg yolks, and vanilla just until combined.  On low speed, slowly pour the egg mixture into the butter mixture and mix just until incorporated.  Scrape the bowl and paddle again, then beat on medium speed for 20 to 30 seconds, or until the mixture is homogeneous.

In a medium bowl, sift together the flour, baking powder, baking soda, and salt.  On the lowest speed, add about one-third of the flour mixture to the egg-butter mixture and mix just until barely combined.  Immediately pour in about half of the buttermilk and continue to mix on the lowest speed until the buttermilk is almost thoroughly incorporated.  Stop the mixer and scrape the sides and bottom of the bowl well.  Again on the lowest speed, add about half of the remaining flour mixture and mix just until barely combined.  Add the rest of the butter milk and mix just until combined.  Be careful not to overmix.

At this point, it is best to finish the mixing by hand.  Remove the bowl from the  mixer stand and, using a rubber spatula, fold in the remaining flour mixture until the batter is just homogeneous.  As you fold, be sure to incorporate any batter clinging to the sides and bottom of the bowl.  Divide the batter evenly between the prepared cake pans.

Bake for 40 to 50 minutes, or until the ops are golden brown and the cakes spring back when pressed in the middle with a fingertip.  Let cool completely in the pans on wire racks.  (The cooled cakes can be tightly wrapped in plastic wrap and stored  in the freezer for up to 1 week.  Thaw at room temperature, still wrapped tightly in plastic wrap.)

To make the ganache frosting:  While the cake layers are cooling, put the chocolate in a medium heat-proof bowl.  In a small saucepan, scald the cream over medium-high heat (bubbles start to form around the edge of the pan, but the cream is not boiling).  Pour the hot cream over the chocolate and let sit for about 1 minute, then slowly whisk together the chocolate and cream until the chocolate is completely melted and mixture is smooth.  Let sit at room temperature for 1 to 2 hours, or until completely cool.  (Or refrigerate the ganache until cool, about 30 minutes, whisking every ten minutes.)

Fit the stand mixer with the paddle attachment (or use a handheld mixer) and beat the butter on medium-low speed for 10 to 15 seconds, or until smooth.  Add the confectioners’ sugar, salt, and vanilla and continue to beat on medium-low speed for about 2 minutes, or until the mixture is fluffy and smooth.  Stop the  mixer a few times and use a rubber spatula to scrape the bowl and paddle to release any clinging butter or sugar.  On medium speed, add the cooled ganache and beat for about 2 minutes, or until completely combined.  Stop to scrape the sides and bottom of the bowl.  Turn up the mixer speed to medium-high and beat for about 1 minute, or until the frosting lightens in color and thickens.  You should have about 4 cups.

Remove the cooled cakes from their pans.  (Be sure they are completely cool.  If they are even the slightest bit warm, the frosting will melt and you will have a mess.)  Using a long, serrated knife, trim the top of each cake to level it (the layers will have rounded a bit in the oven; the trimmed scraps make great nibbles).  Place one cake layer on a cake plate or cake pedestal (if you have a revolving cake stand, use it.)  Spoon about 1 cup of the frosting on top and use an offset spatula to spread it evenly to the edges.

Carefully place the second layer top-side down (so the even sharp edges will be on the top of the finished cake), on top.  Spoon about 1 cup of the frosting on top and spread it over the top and down the sides of the cake, smoothing the frosting as well as you can and covering the entire cake with a thin layer.  This the crumb coat which will keep any loose crumbs from migrating to the surface of the finished cake.  Spoon a heaping cup of frosting on top of the cake, an spread it evenly across the top and down the sides.  This is the finishing layer of frosting.  If desired, spoon any remaining frosting into a pastry bag fitted with a small round or star tip and pipe a decorative line along the top and/or bottom edge of the cake.

The cake can be stored in an airtight container at room temperature for up to 2 days.