I sort of gave up on blogging last week. I took a look at the the state of my house, the length of my to-do list, and the amount of coffee in my pantry and psychologically went on strike. After all, it's not like anything terrible happens if you don't blog for a week.
But I can never ignore the call of the Internet for very long and after experimenting with grapefruit cake again this weekend, I couldn't wait to share my discovery. And that's why I'm a blogger - the compulsion to share is always greater than the desire to keep it to myself (something my teachers may have complained about during my early school years).
At any rate, I've been thinking about grapefruit buttercream ever since I pinned this recipe from The Pastry Affair. That recipe led me to the pink grapefruit cake from Ad Hoc, which I've mentioned my great passion for. But I think of that as a cake you have with a cup of tea (or just passing through the kitchen on your way to somewhere else). I wanted another cake to add to my grapefruit repertoire, one that was festive and suitable for a birthday or other special occasion. The kind of cake you might drink a glass of champagne with.
I had an instinct that my favorite birthday cake, the Simply Delicious Yellow Cake from Amy's Bread in New York, would stand up nicely to grapefruit buttercream. It's not a cake that needs any fixing, so the only tweak I made was to add 1 tablespoon of freshly grated pink grapefruit zest to the batter. After that, I used the buttercream recipe from The Pastry Affair as a basis for mine, though the ratios for my final recipe are different.
It's exactly the cake I'd hoped for. The grapefruit flavor is definitely present, but not as intense as the cake from Ad Hoc. I find there's almost a floral quality to the grapefruit in this cake, with just a hint of tartness. The grapefruit also tempers the sugary overload you get from most traditional buttercreams, giving it a nice balance.
I thought it would be a cake for adults, and the adults were very happy with it (men and women, despite its feminine appearance). But what really surprised me is how much the children liked it, including my finicky five-year-old who declared it "delightful" and ate every bite in record time. Definitely a cake I'll be making time and again.
Pink Grapefruit Layer Cake
(Note: When testing this recipe, I weighed my ingredients instead of measuring them.)
3 cups (420 grams) unbleached all-purpose flour, sifted
1 tablespoon + 1 teaspoon baking powder (20 grams)
3/4 teaspoon kosher salt
1 1/4 cups + 3 tablespoons (340 grams) whole milk
2 teaspoons pure vanilla extract
1 1/4 cups + 2 tablespoons (320 grams) unsalted butter, slightly softened
2 3/4 cups + 2 teaspoons (560 grams) sugar
5 large eggs (260 grams - out of the shell)
1 tablespoon finely grated pink grapefruit zest
1. Preheat the oven to 350℉. Grease two 9-x-2-inch cake pans. Line the bottoms with rounds of baking parchment, grease the parchment lightly, then dust the pans lightly with flour. Shake out the excess.
2. In a large bowl, combine the flour, baking powder, and salt and whisk them gently for even distribution. In a separate bowl combine the milk and vanilla.
3. Using an electric mixer with a paddle attachment, cream the butter and sugar on medium speed until it is light and fluffy, 3 to 4 minutes. Add the eggs gradually, mixing well after each addition, scraping the sides and bottom of the bowl often.
4. Lower the mixing speed to medium-low and add the flour mixture to the butter in 3 parts, alternating with 2 parts of the milk mixture, beginning and ending with the flour. Just toward the end, mix in the grapefruit zest. Mix just until it is evenly incorporated. (This is a thick, fluffy batter, resembling whipped cream. There should not be any lumps or dry pockets of flour remaining. If the batter has a curdled appearance it has not been mixed enough. Increase the speed to medium and mix for another minute or until it is thick and fluffy.)
5. Divide the batter equally between the 2 prepared cake pans. Weighing the batter into the pans is the most accurate way to do this. This ensures that both layers are uniform in size, and finish baking at the same time. You'll have approximately 930 grams of batter per pan. The pans should be about 2/3 full. Smooth the batter so it fills the pans evenly. Place the pans on the center rack in the preheated oven. Bake them for about 35 to 40 minutes, or until the cake is almost ready to pull away from the side of the pan and a toothpick inserted into the center of the cake comes out with a few moist crumbs.
6. Cool the pans on a rack for 10 minutes, then invert them onto a wire rack that has been sprayed with cooking spray and lift off the pans. Cool them on the rack completely. Before frosting, be sure to remove the parchment from the bottom of each layer. While the layers are cooling, prepare the frosting.
1 cup freshly squeezed, strained pink grapefruit juice
1 tablespoon freshly grated pink grapefruit zest
6-7 cups powdered confectioners' sugar, sifted
1 cup (2 sticks) unsalted butter, room temperature
1. Put grapefruit juice in a small saucepan and bring it to a boil. Reduce heat, then simmer until grapefruit juice is reduced to approximately 3 ounces (this will thicken the grapefruit juice a bit, while concentrating the flavor). Remove from the heat and let it cool to room temperature.
2. In a standing mixer with the paddle attachment, beat the butter and zest together on medium-high until smooth. Reduce the speed to medium and beat in 2 ounces (1/4 cup) of the grapefruit syrup.
3. Beat in sifted powdered confectioners' sugar, 2 cups at a time, until smooth. After you've added 6 cups of the sugar, test your buttercream. If it needs to be thinned, add grapefruit syrup 1 tablespoon at a time until you've reached the desired consistency. If the frosting needs thickening, add 1/2 cup of the sugar at a time until you've reached the desired consistency.
If you need a baking scale, see my previous post for a recommendation. It's inexpensive and absolutely worth it!
To get the finest possible zest, I use a Microplane zester. I've had mine for more than a decade and it's still amazing.