Mandy Merriman's dark chocolate huckleberry shake cake recipe

Mandy Merriman joined "Good Morning America" on Friday to celebrate the debut of her new cookbook, "I'll Bring The Cake: Recipes for Every Season and Every Occasion."

Merriman whipped up one of her favorite confections and shared the full recipe below with "GMA" along with helpful tips for novice bakers, printed below the recipe.

Dark Chocolate Huckleberry Shake Cake

"Have you ever had a big salad and then wanted to balance it out with a giant milkshake? (Asking for a friend.) My family loves a local restaurant called Cubby's. Whenever we go, I order their tri-tip steak salad -- but then I can't help but get their Hucklelala shake on my way out. It's flavored with huckleberry syrup and mixed with tiny bits of dark chocolate. With every sip, you get that creamy huckleberry flavor and a few dark chocolate pieces that linger afterward on your tongue. The first time I tried it, I knew right away it needed to be a cake."

This shake-to-cake has rich dark chocolate cake layers flavored with a little bit of that same huckleberry syrup and huckleberry buttercream flecked with little bits of dark chocolate.

Ingredients

Dark Chocolate Huckleberry Cake
3/4 cup buttermilk (room temperature)
2/3 cup sour cream (room temperature)
3 large eggs, plus 1 egg white (room temperature)
1/3 cup vegetable oil
1 tablespoon pure vanilla extract
1/4 cup cocoa powder
1 box dark chocolate cake mix
1/2 cup huckleberry syrup
 Huckleberry Buttercream with Dark Chocolate Bits
1 cup chocolate chips
1 1/2 cups (3 sticks) unsalted butter
1/4 cup huckleberry syrup
1/4 cup heavy cream (plus more if needed)
1 tablespoon pure vanilla extract
Pinch of salt
8 1/2 cups powdered sugar
 For decorating
Dark chocolate bits
Dark chocolate chunks

Directions

For the Dark Chocolate Huckleberry Cake

Preheat the oven to 325 F, then prep three 6-inch round cake pans with a swipe of shortening and dusting of flour to prevent sticking.

In a large bowl, whisk together the buttermilk, sour cream, eggs, oil, and vanilla until thoroughly combined. Sift in the cocoa powder and cake mix and whisk until just combined. Do not overmix. Split the batter evenly among the prepared pans.

Bake for 30 to 32 minutes, until the center is baked through. Let the cakes cool in the pan for a minute before flipping out onto a wire rack to cool completely. Poke holes in the bottom of each cake round with a toothpick, then brush on the huckleberry syrup to soak. Wrap and freeze the cakes before assembly.

For the Huckleberry Buttercream

In a food processor, pulse the chocolate chips until they're chopped into small bits. You should have about 1/2 cup.

In the bowl of a stand mixer fitted with a paddle attachment, beat the butter on medium speed until it's light and fluffy. Add the huckleberry syrup, heavy cream, vanilla, and salt and beat again until combined, then scrape down the sides with a spatula.

With the mixer on low speed, add the powdered sugar about 1/2 cup at a time. The buttercream will be thick. Add a little more heavy cream, 1 tablespoon at a time, to thin it out if needed, and then flip the mixer to high speed and beat until the buttercream is lighter in color and texture, about 2 minutes. Toss in the dark chocolate bits and mix on low speed until just combined.

To assemble

Place a cardboard cake round on a cake turntable. Dot a little bit of buttercream in the center of the round and spread it out with an angled icing spatula. Place the first chilled cake layer in the center. Add a layer of buttercream. Place the next cake layer on top, then repeat, making sure to line the layers up evenly. After adding the top cake layer, crumb coat the cake by spreading a thin layer of buttercream around the entire cake. Freeze for 2 minutes to set the buttercream.

Using a wooden spoon, beat out any air bubbles in the remaining buttercream. Finish frosting the cake as desired or follow the decorating instructions below.

To decorate the cake

Spread the remaining buttercream on the top and sides, using a cake scraper for smooth sides. Leave the top edge uneven for a more rustic finish.

To finish, press on some dark chocolate bits along the bottom rim of the cake, and sprinkle some dark chocolate bits and chocolate chunks on top.

Tip: For the dark chocolate bits, just pulse dark chocolate chips in a food processor until little pieces form. The smaller, the better. Since fresh or frozen huckleberries are hard to find, I use huckleberry syrup, which you can find with the other soda flavorings at your local grocery store.

Additional tips for baking cakes

You don't have to do it as a stacked cake, you can do it as a sheet cake too in a 9-by-13-inch sheet pan.

Home bakers see recipes and see a bunch of different elements and get intimidated, they can split up the process by baking the cake the first day and putting in fridge. Then the next day they frost it, which makes it much easier to frost.

Freeze your cake rounds and wrap in plastic wrap and stick into freezer, which helps seal in the moisture.

Using room temperature ingredients makes for a softer more fluffy cake and makes it easier to stir them into the other ingredients.

Check rising agents. Use recently purchased baking powder and soda to make sure it's not sitting on your shelf and use it within a month or two, otherwise it can make cookies flat.

Two main tools to have when baking a cake: a cake scraper -- big metal rectangle -- and turntable will help up your baking game if you are new.

Cakes lean because people put in too much filling between the cake layers. If you are frosting it, you can stick a wooden dowel down the middle to keep it standing up straight.

Don't skip the crumb coat. A thin layer that you put on right after you stack it helps to hold the shape. After you crumb coat, put it in the freezer for 5 minutes before frosting.

Get at eye level when you are frosting the cake and make sure it's flat before you add the next layer.

Box mix isn't cheating. A lot of bakeries use a doctored cake mix at bakeries. Use it and then add egg whites or egg yolks, vanilla, buttermilk, sour cream to enhance the flavor. And use vegetable oil instead of butter for a more fluffy and soft cake. Hand mix everything then use a hand mixer.

Reprinted with permission from I'll Bring The Cake by Mandy Merriman. Copyright © 2023 by Mandy Merriman. Reprinted by permission of Harvest, an imprint of HarperCollins Publishers.