Irish Trinity Cake

My brother's birthday falls around Saint Patrick's Day, and every year we celebrate with a corned beef dinner. Traditionally, he has always asked for a marble cake with chocolate frosting, but this year I suggested something different.

I thought this cake would be a welcomed departure from tradition, because what's not to like? Guinness chocolate cake, Jameson tinted ganache filling, and Bailey's frosting: an Irish (holy) trinity. Forever, and even, amen.

This is a fantastically rich cake with bold flavor that is perfect for any Saint Patrick's Day celebration!

Irish Trinity Cake

Source: Adjusted from Beantown Baker/Smitten Kitchen
Yield: One 3-layer 8" or 9" cake
Preparation time: 45 minutes
Cook time: 30 minutes
Total time: 3 hours

Ingredients

For the cake:

• 2 cups Guinness
• 2 cups unsalted butter (4 sticks)
• 1 1/2 cups cocoa powder (dutch processed preferred)
• 4 cups flour
• 4 cups sugar
• 1 tablespoon baking soda
• 1 1/2 teaspoons salt
• 4 eggs, at room temperature
• 1 1/3 cups sour cream

For the ganache filling:

• 16 ounces bittersweet chocolate
• 1 1/3 cups heavy cream
• 4 tablespoons butter
• 1 tablespoon Irish whiskey (optional)

For the frosting:
• 1 1/2 cups unsalted butter, at room temperature (3 sticks)
• 1 1/2 pounds powdered sugar
• 4 tablespoons Bailey's Irish cream (can subsitute milk or cream)

Instructions

For the cake:

1. Preheat oven to 350°F. Prepare three 8" or 9" cake pans*. Bring Guinness and butter to simmer in heavy large saucepan over medium heat. Add cocoa powder and whisk until mixture is smooth. Cool slightly.
2. Whisk flour, sugar, baking soda, and salt in large bowl to blend. Using electric mixer, beat eggs and sour cream in another large bowl to blend.
3. Add Guinness-chocolate mixture to egg mixture and beat just to combine.
4. Add flour mixture and beat briefly on slow speed. Using rubber spatula, fold batter until completely combined.
5. Divide batter evenly among cake pans, filling about 2/3 of the way full.
6. Bake cake until a toothpick inserted into center comes out clean, rotating them once front to back if your oven bakes unevenly, about 30 minutes. Cool cakes on a rack completely.
For the ganache filling:
7. Chop the chocolate and transfer it to a heatproof bowl. Heat the cream until simmering and pour it over the chocolate. Let it sit for one minute and then stir until smooth. Add the butter and whiskey and stir until combined.
For the frosting:
8. Whip the butter in the bowl of an electric mixer, or with a hand mixer, for several minutes. You want to get it very light and fluffy. Slowly add the powdered sugar.
9. When the frosting looks thick enough to spread, drizzle in the Baileys (or milk) and whip it until combined. If this has made the frosting too thin (it shouldn’t, but just in case) beat in another spoonful or two of powdered sugar.
Assembly:
10. Level cake layers with a large serrated knife. Pipe a ring of frosting around the edge of the first layer to build a dam for the ganache. Spread a thick layer of ganache over the top of the layer.
11. Repeat with second layer, then top the with the third cake layer.
12. Frost outside of the cake with remaining frosting and decorate as desired.

*I only have two pans; you can bake 2 cakes, cool slightly and remove one from the pan, cool the pan and then bake the third.

Cakes can be baked one or two weeks in advance, and stored in the freezer, well wrapped. They do not need to be thawed before assembly, but the cake should then sit at room temperature for several hours before serving.