Tessa Huff's Riesling Rhubarb Crisp Cake
One of my favorite non-cake desserts is a strawberry rhubarb crumble that my father-in-law makes every summer during our visits to Los Angeles. Though a hot dessert, the flavors scream summer and when you combine it with a cold scoop of vanilla bean ice cream, it's pretty much perfection in my book.
So, when I got Tessa Huff's new cookbook, Layered, and was browsing the recipes, I knew this cake would be the first one I'd make. It's basically my father-in-law's strawberry rhubarb crumble in a cake. It was the obvious choice.
The only change I made before even trying the recipe "as-is" was substituting the sweet Riesling for sparking white grape juice. I don't drink wine (or any alcohol, for that matter) and know that many of my readers prefer not to bake or cook with alcohol either, so I chose to find an alternate bubbly drink that would (hopefully) give the cake the same moisture and sweet flavor the Riesling does. And, I'm happy with the outcome: the cake is light and fluffy, sweet and has a slight hint of the white grape juice, which I think pairs well with the other flavors in the cake.
I was also a huge fan of the rhubarb strawberry compote and the crumble! I could have eaten both of those by the spoonful. (Who am I kidding? I did eat them both by the spoonful... it was MY Mother's Day cake, after all!)
As for the swiss meringue buttercream, I've got to be honest, I didn't love it. The buttercream mixed with the compote in the middle layers of the cake was good because it had a good flavor thanks to the sweet rhubarb and strawberries. However, the plain swiss meringue buttercream was kind of bland. Because this cake is so light and fluffy, I think the frosting could be a little denser and more flavorful.
That being said, I was so grateful to Tessa for providing so many helpful tips about making the swiss meringue buttercream. (She's got tips and troubleshooting sprinkled throughout the entire cookbook. It's one of my favorite parts of the entire book.) In the past, I've had far more failed attempts at this type of frosting than successes, but as I followed Tessa's directions and read her extra tips, I was really happy with how the buttercream turned out. Huge success right there!
Because I think Tessa's tips were so helpful in making the swiss meringue buttercream, I want to give you a brief rundown of what she advises:
1. You want to make sure that your mixing bowl is completely clean and completely dry. You don't want any traces of grease in your mixing bowl and you don't want any remnants of egg yolk in your egg whites.
2. It's important to mix the egg whites and sugar before place them on the heat because the egg whites could cook on their own.
3. You want your water simmering, not boiling.
4. Use your inner wrist to test the outside of the mixing bowl after mixing. (This was news to me, and I could totally tell a difference between how the bowl felt against my inner wrist and my palm. Your inner wrist will give you a more accurate read of the temperature.)
5. If your butter is too cold, your buttercream will likely curdle in the final stages of mixing. If this happens to you, you can try to keep mixing to incorporate the cold butter. If that doesn't work, Tessa suggests removing some of the buttercream and heating it in the microwave until it's melted (but not hot). Then, turn the mixer back on and slowly add the buttercream.
6. If your mixture becomes soupy, you can stick it in the refrigerator for a little while and try mixing again.
7. You can run the mixer on low speed to get out air bubbles.
I definitely think you should try this cake "as-is" your first time around. See what you think of the swiss meringue buttercream,and if you're like me and don't love it, you can always use a traditional buttercream in the future. I just always think it's a good idea to make the recipe the way the author intended (or as close as possible) so you know what it's supposed to taste like before making any personal changes.
Riesling Rhubarb Crumble Cake (recipe source: Layered, by Tessa Huff)
Yield: one, 8-inch, 3 layer cake
Ingredients
For the Cake
3 1/4 cups (425 g) cake flour, plus more for the pans
1 tablespoon plus 1/2 teaspoon baking powder
3/4 teaspoon salt
1 cup (2 sticks / 225 g) unsalted butter, at room temperature
2 cups (400 g) granulated sugar
2 teaspoons pure vanilla extract
6 large egg whites
1 1/2 cups (360 ml) sparkling white grape juice (original recipe calls for sweet Riesling)
For the Rhubarb Strawberry Compote
1 3/4 cup (8 ounces / 225 g) fresh strawberries, hulled and quartered
1 cup (4 ounces / 115 g) fresh rhubarb, cut into 1/4-inch pieces
1/4 cup (50 g) granulated sugar
2 tablespoons fresh lemon juice
For the Swiss Meringue Buttercream
1 cup (240 ml) large egg whites
2 cups (400 g) granulated sugar
3 cups (6 sticks /675 g) unsalted butter, at room temperature, cubed
1 tablespoon pure vanilla extract
For the Rhubarb Buttercream
2 cups of swiss meringue buttercream
1/2 cup (120 ml) Rhubarb-Strawberry Compote (above)
For the Oat Crumble
1/2 cup (45 g) quick-cooking oats (don't sub with rolled oats!)
1/4 cup (25 g) sliced almonds
1/4 cup (55 g) firmly packed brown sugar
1/4 cup (30 g) all-purpose flour
3 tablespoons unsalted butter, at room temperature
2 tablespoons honey
1/2 teaspoon ground cinnamon
1/4 teaspoon salt
Instructions
For the Cake
1. Preheat your oven to 350 degrees F. Spray, add parchment, spray again, and then flour three 8-inch round cake pans. Set aside.
2. Sift together the flour, baking powder and salt. Set aside.
3. Place the butter in the bowl of a stand mixer fitted with the paddle attachment and beat on medium-high speed until smooth. Add the sugar and mix on medium speed until the mixture becomes light and fluffy. This will take about 3 to 5 minutes. Once light and fluffy, turn the mixer off and scrape down the sides of the bowl.
4. Turn the mixer to medium-low speed and gradually add the vanilla and egg whites until combined. Stop the mixer and scrape down the sides of the bowl again.
5. With the mixer on low speed, add the flour mixture, alternating with the sparking white grape juice or Riesling, beginning and ending with the flour mixture. Mix on medium speed for about 30 seconds once the last remains of the dry ingredients are combined. Don't over mix.
5. Evenly divide the batter among the prepared pans and bake for 23 to 25 minutes. Cakes are done with a toothpick inserted into the middle comes out clean. Let them cool for 10 to 15 minutes before inverting cakes onto cooling racks to cool completely.
For the Rhubarb Strawberry Compote
1. Add the strawberries, rhubarb, sugar and lemon juice in a medium saucepan over medium-high heat, stirring occasionally. Once the juices start to bubble, turn the heat down to medium-low and let the mixture simmer for 8 to 10 minutes. Remove the pan from the heat and let the mixture cool completely.
For the Swiss Meringue Buttercream
1. In the bowl of a stand mixer, combine the egg whites and sugar and whisk by hand until blended. Fill a medium saucepan with a couple inches of water and place it over medium-high heat. Put the heat-proof mixing bowl on top of the sauce pan, but make sure it's not touching the water. You're essentially creating a double broiler.
2. Heat the egg mixture until it reaches 160 degrees F on a candy thermometer, whisking occasionally. Once it's hot, use hot pads to transfer the mixing bowl back to the stand mixer.
3. Using the whisk attachment, beat the egg white mixture on high speed for 8 to 10 minutes, until still peaks form and can hold their form. The outside of the bowl should be back to room temperature and no heat should be escaping the meringue from the top of the bowl. Stop the mixer and change the whisk attachment to the paddle attachment.
4. Turn the mixer to low speed and add the butter, a few tablespoons at a time and then add the vanilla. Once the butter and vanilla are incorporated, turn the speed to medium-high and beat for about 3 to 5 minutes, until the buttercream is silky.
5. To store swiss meringue buttercream, transfer the buttercream to an airtight container and either refrigerate it for up to 10 days or freeze it for up to 2 months. Return to room temperature before remixing.
For the Rhubarb Buttercream
1. In the bowl of a stand mixer fitted with the paddle attachment, mix 2 cups of the buttercream until silky and smooth. Add 1/2 cup of the cooled rhubarb compote and mix until combined.
For the Oat Crumble
1. Preheat your oven to 375 degrees F. Line a baking sheet with parchment paper and set aside.
2. In a medium bowl, combine the oats, almonds, brown sugar, flour, butter, honey, cinnamon and salt. Mix by hand with a wooden spoon until the mixture resembles clumps of sand. Spread the crumble over the parchment paper and bake for 8 to 10 minutes, stirring halfway through. The crumble should be golden brown. Let it cool completely and then crumble the mixture into smaller pieces, if needed.
Assembly
1. When the cake layers have cooled completely, level each layer and place the first layer on a cake plate or cake stand.
2. Spread 1 cup of the Rhubarb Buttercream on top of the first layer, using an offset palate knife. Sprinkle about 1/2 cup to 3/4 cup of the crumble on top of the buttercream. Using the back of your fingers, gently press the crumble into the buttercream.
3. Repeat step 2 with the second cake layer and buttercream/crumble layer.
4. Place the third cake layer on top of the buttercream and crumble layer, top-side down.
5. If using food coloring, add to the remaining buttercream and use it to frost and decorate the rest of the cake.