Heavenly Chocolate Cake with Chocolate Custard Frosting

This is one of the best chocolate cakes I've ever made. So far I've made it as a birthday cake for both my brother and my brother-in-law and tripled the recipe to make 72+ cupcakes for a retirement celebration honoring one of the assistant district attorneys with whom I've worked for the last three years. For those of you who choose to make this recipe for cupcakes, there will be a good bit of leftover frosting. I don't mind this at all because it freezes beautifully and makes life much easier in the future!

Thankfully when I made all those cupcakes in my non-commercial kitchen on a Monday night, I had the assistance of my friend and neighbor, Traci. It was a late night, but would have been FAR later without her awesome help!

Heavenly Chocolate Cake with Chocolate Custard Frosting
adapted from epicurious

Makes one 9" cake or ~24 cupcakes

Heavenly Chocolate Cake
In a large electric mixing bowl, combine:
1 cup butter, softened
1 cup brown sugar
3/4 cup granulated sugar
Cream together until light and fluffy, about 4 minutes.

One at a time, mix in:
4 large eggs
After each addition, scrape down side of the bowl.

Mix in:
2 oz unsweetened chocolate, melted and slightly cooled
1 1/2 teaspoons vanilla

In a medium bowl, sift together:
2 cups flour
2/3 cup unsweetened cocoa powder
1 1/2 teaspoons baking soda
1/2 teaspoon salt
Add 1/3 of the dry ingredients to the electric mixing bowl. Mix until just incorporated. Scrape down sides of the bowl. Alternate adding remaining dry ingredients with adding:
1 1/2 cups buttermilk

For cake, pour into two 9" cake pans, greased and floured. Bake 30-35 minutes. Let cool in pans for 10-15 minutes before removing and setting on wire cooling rack to finish cooling. Let cool completely before frosting.

For cupcakes, ~1/3 cup batter into lined cupcake tins. Bake 20-25 minutes. Transfer to wire cooling rack. Let cool completely before frosting.

Chocolate Custard Frosting
In a medium saucepan, heat:
2/3 cup whole milk

In a large electric mixing bowl, whisk together:
3 large egg yolks
1 tablespoon + 1 teaspoon flour
1/3 cup confectioners sugar
Whisking constantly, slowly add about half of the heated milk to the eggs. Transfer back into the saucepan and bring custard to a simmer, whisking together for about 2 minutes. At this point, the custard will be thick.

Transfer the thickened custard back to bowl. Cover with plastic wrap so that the plastic is directly on top of the custard. Place in refrigerator until cool, about 45 minutes.

Remove custard from the fridge and add:
1 teaspoon vanilla
1 cup confectioners sugar
Using whisk attachment, beat on medium until ingredients are evenly incorporated.

Two tablespoons at a time, whisk in:
1 1/2 cups unsalted butter, softened

Finally, add:
10 ounces bittersweet chocolate, melted + cooled
Beat until well incorporated.

Frost cake/cupcakes. Decorate as desired.

Eat up!