Grapefruit Curd in Grapefruit Cake
We had an avocado tree in our backyard growing up, in one of the more concrete-y neighborhoods of central Los Angeles. It was the humble avocado tree behind the kinda-rusted, maybe a little dangerous, still totally playable swing set in our patchygrass, mangy dog wandering, backyard.
I think of the relentless to-do list my parents upheld while my sister and I were kids… things like: go to work, survive work, have food in the house, pay the light bill, raise not asshole children… having a fluffy-grassed backyard wasn’t a huge priority. But this avocado tree in the corner of backyard was a little oasis! I should tell you now that it had no avocados. Never did. Not even one time… I know because I would check ALL THE TIME. It did however, provide a small ring of shade at most points in the afternoon and it was a fine tree with upstanding morals and values.
At some point in my 18 years of living in that house and tip toeing around that backyard, someone mentioned that we had a male avocado tree which… well, it seemed rather strange that this tree would have a gender. I often wondered (once I was old enough to wonder such things), if there was a female avocado tree in a neighboring backyard that was just bursting with fruit because of our humble, unassuming, un-avocado-ing male avocado tree.
Likely not. It’s not that we had a male avocado tree, it’s that avocado trees have this very delicate fruit bearing system. I know you’re curious so I’ll explain it to you before we talk about grapefruit cake. We’re definitely going to talk about cake. See… avocado tree flowers have both male and female parts but they don’t release those parts at the same time. A flower opens and releases its female parts first. Closes. Then the male parts open, and then close. All the while waiting for the right bee at the right time to take the right pollen to the right flower. AKA: Earth is amazing… and we probably just needed a buddy tree for our avocado tree for them to both pollinate and flourish and provide more than greenery and shade.
I say all of this to say that big beautiful fruit (we’re talking about grapefruit now) that emerges from small flowers is, if you think about it and we’re thinking about it, AMAZING… and should be turned to curd and into cake (and if you’re an avocado, definitely guacamole). If you’re lucky enough to have a grapefruit (or avocado) tree in your backyard… or in your neighbor’s yard within stealing distance… you should hug it and thank all of the bees around you.
And now we’re going to make a cake.
Curd and cake. Both with grapefruit. Both from scratch.
First the curd. Citrus curd, which we should be making my the pint-full right now, is a rich, slow stove top custard with grapefruit juice and a pinch of ground cloves.
To start the curd, grapefruit juice (fresh squeezed is preferable) is simmered on the stoptop to reduce the juice and intensify the flavor. While the juice simmers, butter and sugar are whipped together in a heat-proof metal bowl. This bowl will turn into a double boiler, so we need it to conduct heat.
Egg yolks are whisked into the butter and sugar mixture. Egg yolks and whole eggs will work to thicken the curd.
How long before we’re weirded out by the word ‘curd’? Is it already happening? (Yes.)
The reduced grapefruit juice is cooled slightly and whisked into the butter, sugar and egg mixture. Whisked well, it becomes a bit frothy on top. We’re on the right track.
In a small pot, bring a few inches of water to a boil and place the metal bowl over the simmering water. It’s a double boiler, and it’s a gentle way to coax our eggs into slowly thickening into a spreadable curd.
With constant whisking (which means no multi-tasking) the mixture will thicken to a warm pudding consistency after 8 to 10 minutes.
We’ve got our curd and now it’s time for cake.
Easy cake times thanks to Food52. We’re not going to over-complicate things here.
Softened butter and sugar are creamed together with grapefruit zest until very pale and fluffy. Hand mixer or stand mixer, but really fluff the butter.
The grapefruit curd is cooled slightly and 3/4 cup of our tangy grapefruit curd is added to the butter and sugar mixture.
Eggs are then beaten into the mixture, one by one.
Self-rising flour (flour + baking powder + salt) is added to the fluffy curd batter, making this recipe. No fuss.
If you don’t have self-rising flour on hand, make your own self-rising flour just like this!
The batter is spooned into an 8-inch pan and another 3/4 cup of grapefruit curd is lightly swirled into the batter.
We’re great. Now is a good time to acknowledge that.
Baked to golden brown, the curd caramelizes a bit while the cake is tremendously tender.
It’s the prefect afternoon tea cake, or morning coffee cake, or midnight snack with milk cake. It’s cake. Whenever and however. This is the kind of cake you hope to casually have on hand when your neighbors casually drop by unexpected on a weekend afternoon. You hope hope hope that the stars align and you have this cake to offer them. I say bake the cake, open the windows, and see if you can lure them over.
- 1 cup freshly squeezed grapefruit juice, seeds strained
- 5 tablespoons unsalted butter, softened to room temperature
- 1/2 cup granulated sugar
- 2 large egg yolks, at room temperature
- 2 large eggs, at room temperature
- 1/8 teaspoon sea salt
- 1/8 teaspoon ground cloves
- 1 tablespoon freshly squeezed lemon juice, strained
- 6 ounces (1 1/2 sticks) unsalted butter, at room temperature
- 1 tablespoon fresh grapefruit zest
- 3/4 cup granulated sugar
- 1 1/2 cups grapefruit curd
- 3 large eggs
- 1 3/4 cup plus 1 tablespoon self-rising flour
- To make the grapefruit curd, in a small saucepan, simmer grapefruit juice. Simmer and reduce from 1 cup to 1/2 cup. Remove from heat and allow to cool slightly.
- In a medium heatproof bowl (a metal bowl is best), stir together butter and granulated sugar until well incorporated and fluffy. I used a wooden spoon and some elbow grease. Using a whisk, add the egg yolks and whisk to combine. Add the eggs, one at a time, beating for one minute between each addition. Whisk in the salt and cloves and lemon juice. The mixture will seem slightly curdled. That's ok. Slowly stream in and whisk the slightly cooled grapefruit juice until evenly combined.
- In a small or medium saucepan (I used the same saucepan I used to reduce the grapefruit juice), bring a few inches of water to a simmer. Place the heatproof bowl over the simmering water , making sure that the bottom of the bowl does not touch the simmering water.
- Whisk constantly. The sugar will begin to dissolve and the mixture will begin to thicken. This take between 8 and 10 minutes of near constant whisking. If you stop whisking, the eggs in the mixture may create lumps so keeeeeep whisking.
- Once thickened to the texture of warm pudding, remove the bowl from the simmering water and transfer to a small bowl. Allow to rest in the refrigerator while you make the cake.
- Place a rack in the center of the oven and preheat oven to 350 degrees F. Line the bottom of an 8-inch round baking pan with parchment paper, grease the pan and set aside.
- To make the cake, in the bowl of an electric stand mixer fitted with a paddle attachment, or in a large bowl with a set of hand beaters, beat together butter, sugar, and grapefruit zest until pale and fluffy, 3 to 5 minutes. Add half of the grapefruit curd and beat to combine. Add the eggs, one at a time, beating for 1 minute between each addition. Add the flour and use a wooden spoon to fold together until thoroughly combined.
- Spoon the batter into the prepared pan. Top with the remaining grapefruit curd and use a butterknife swirl the curd just slightly into the cake. Bake for 35 to 45 minutes until a skewer inserted in the center comes out with moist crumbs.
- Allow to cool for 15 minutes before transferring to a wire rack to cool completely.
- Serve in big wedges with warm tea.