Stop: Before you tell me “Plums aren’t keto!”, let me assure you that they are used only as a flavor enhancer in this rich, buttery curd. Besides, plums have fewer carbs than blueberries, which are used abundantly in the keto diet—which means that this recipe is low in carbs but very big on flavor. So why not swap your plain old lemon curd for this exciting, beautifully colored plum curd? Just give it a try and you’ll fall instantly in love. It tastes scrumptious on bread, with pancakes, as a pie filling… I’ve included some photos on how I use the curd, feel free to invent your ways to use it!
Tips for preparing the Keto Plum Curd
If your plums are large, halve or quarter them. I don’t remove the pits from my plums: that would be an insane amount of work and practically impossible, too, because if you try to remove the pits, you’ll also lose plenty of precious flesh. If you can easily remove the pits, by all means do so, but I prefer to leave them in and just cook the whole plums until soft. Getting rid of the pits afterwards is easy: just press the soft, cooked plums through a mesh strainer.
When cooking the plums, be sure that the liquid has evaporated almost completely. After removing the pits, you should have a maximum of 1 cup (240 ml) plum puree. Also, when cooking the plums, take a peek at them every once in a while to prevent them from burning and getting stuck to the bottom of the saucepan. The fluid can evaporate on the sly, so it really is a good idea to keep your eye on them. (When I was cooking a lot of plums in a large saucepan, the liquid evaporated because I hadn’t checked on them, and I burned the plums into a thick, black layer that covered the bottom of my saucepan. I tried to clean the saucepan; our cleaners tried to clean it; and finally my husband succeeded in getting rid of the black stuff in the saucepan. Take precautions so you don’t run into similar issues! My husband won’t be able to come and take care of the mess for you!)
Oh yes, and to reduce the carbs as much as possible, use as sour plums as you can find. That might be a bit difficult, as most types of cultivated fruit are abnormally sweet nowadays.
Also, if your plums are on the sweet side, feel free to adjust the amount of sweetener. My plums are so sour that they need 2/3 cup (160 ml) powdered erythritol to balance them out.
And speaking of sweeteners, powdered sweetener (erythritol, that is) is a must. Never, ever use erythritol crystals in any cold dessert! The result will be unpalatably gritty. Either that, or the erythritol will form large, transparent chunks. And if you use too much powdered erythritol, it will create minuscule particles that create a weird mouthfeel. So, if you need to use more than 1 cup (240 ml) powdered erythritol, it’s a good idea to use another sweetener — like stevia — in addition to prevent those tiny particles from forming.
As for butter, I recommend using salted butter. Salt rounds out the flavors in both sweet and savory dishes. If you have only unsalted butter, add a pinch of salt.
So, this is a relatively easy recipe: it just requires some cooking time. But the actual hands-on time is minimal: most of the time you just let the plums cook and the curd chill.
For these progress photos, I’ve simplified the process even further. You might realize that in the video, I first let the butter and the sweetener melt in the plum puree and then add the eggs. Well, I noticed that you might as well add everything — the sweetener, butter, and the eggs — to the saucepan with the plum puree at the same time. The result is just as good as when you add them separately. Just remember to whisk the mixture like there’s no tomorrow while you heat it! Didn’t get it? No problem! Soon you will! Let’s take a closer look at how to prepare this beautifully tangy treat:
Wash the plums well.
Take a medium saucepan and add the plums…
…and a little bit of water.
Bring to a boil over medium-high heat. Reduce the heat to a minimum.
Let simmer for 2-3 hours. These plums have been cooking for 1 hour now:
Now they are ready! Notice that almost all the fluid is gone.
Press the mixture through a mesh strainer with a back of a large spoon…
…so that only the pits remain in the strainer. Like this:
Discard the pits. You should now have no more than 1 cup (240 ml) plum puree left.
Transfer the plum puree to a medium saucepan (if you don’t have it in there already). Add the sweetener…
…and the eggs.
Heat the mixture over a low heat, whisking vigorously all the time…
…until the mixture gets thicker and smoother, and the first bubbles appear. Don’t let it boil, whatever you do!
Let cool to room temperature, then refrigerate overnight. Now it’s really thick:
The next day, transfer the curd to jars…
My plum curd experiments
This year, our little plum tree produced an unbelievably huge amount of plums. Last year, we got only one or two quarts (≈ liters). Guess how much it made this year? About 70 quarts (≈ liters)! Yep, we were drowning in plums. This is part of the crop:
So, I didn’t have any other choice than to start inventing ways to use those plums. Actually, that was a super-fun task, but quite a laborious one — and I didn’t have a lot of free time, because I’m in the middle of writing my Finnish ketogenic vegan book and I have my regular language technology projects going on. The deadline for the book is approaching at lightning speed! Yikes. But for a few days, I found the time (somewhere!), rolled up my sleeves and made keto plum marmalade, keto plum jam (including spicy versions for the holiday season), sugar-free plum chutney (developed a nice recipe for my keto-vegan book while I was at it, actually!), keto Rumtopf, and sugar-free plum juice. After all that, my fridge was stuffed with plum conserves — and I still had two full buckets of plums left. Sigh.
Here’s the Finnish version of the Sugar-Free Plum Chutney that will be in my book:
What else could I create from plums? Something that would fit a keto lifestyle (and the space left in my fridge!)? Then it hit me: plum curd! I’m an avid fan of lemon curd — or any type of citrus curd. I’ve made lots of different versions of citrus-fruit based curds over the years. My ultimate favorite is the triple-citrus curd I once created for my newsletter. But since our plums are super-sour, maybe they would make a great curd, too? A curd would have some precious fats and eggs in it, too, and the amount of plums is small so that the carb count wouldn’t skyrocket. Plus, you usually use just a tablespoon or two of curd per serving, which means plenty of fat but few carbs. That sounded like a winner!
Next, I needed to do some careful calculations. First, I needed plums and some water to cook them in. 1 lb (450 g) sounded like a good place to start. My lemon curd recipe uses 1/2 cup (120 ml) lemon juice. How much plum puree I’d have left after cooking the plums remained to be seen.
After I had cooked the plums for a couple of hours, I pressed them through a mesh strainer: I got rid of the pits and was left with 1 cup (240 ml) of smooth plum puree.
Hmm: if my lemon curd using 1/2 cup (120 ml) lemon juice needed three eggs and 3.5 oz (100 g) butter, I’d need to use more for the plum curd, since the volume of the plum puree is double the volume of the lemon juice. On the other hand, the plum puree was thicker than the lemon juice, so I most likely wouldn’t need to double the amount of eggs and butter—just add a little more. I ended up experimenting with 3 eggs and 4 oz (115 g) butter.
My lemon curd uses 1/2 cup (120 ml) erythritol crystals. (Eek, not powdered erythritol?! Why did I use erythritol crystals and not powdered erythritol? Oh yes, now I know why: the recipe is so old that there was no powdered erythritol available at that time! Just erythritol crystals. Nobody was even talking about powdered erythritol back then. I made a mental note to modernize that lemon curd recipe!)
Anyway, I thought 2/3 cup (160 ml) powdered erythritol might make my plum curd sweet enough, so I added that to the plum puree together with the butter. I heated the mixture carefully until the sweetener and the butter had melted.
Then I added eggs, one at a time, beating well after each addition. I didn’t dare to add them all at once — I don’t know why. Maybe I was afraid that the mixture would separate or become lumpy.
I continued heating the mixture, whisking all the time. Soon it got thicker and started steaming. After the first bubbles appeared, I removed the saucepan from the heat. The mixture looked quite thick, but I knew I’d only get a sense of the final result after the curd was completely chilled. Now it was still relatively runny, but I was hoping it’d get stiffer in the fridge.
The next day, I took my plum curd experiment from the fridge and checked it. The consistency was perfect: thick, yet spoonable. And the taste, then: It was a-m-a-z-i-n-g! Sweet — yet tangy — buttery, rich, and elegant. I don’t have anything against a good ol’ lemon curd, but this was so much better, and so much more exciting!
I still wondered whether I could simplify the preparation even further. What would happen if I added the sweetener, butter and eggs all at once and heated the mixture while whisking all the time? Would that make it lumpy? Cause it to separate? I had to find out!
To my surprise, the curd made with the simplified method was just as good as the one made with the more complicated method. I also tried this simplified version with more sweetener—1 cup (240 ml) powdered erythritol—to see if I could improve the taste further. And later I realized that instead of 3 eggs, I had added 4 by accident. It didn’t make any difference to the consistency! Can you imagine?! Anyway, I liked this simplified version a lot, but the 2/3 cup (160 ml) sweetener was better. 1 cup (240 ml) made it too sweet. Since I had so much plum curd, I made some keto pancakes (made with lupin flour), and topped them with the curd:
A closer look:
…and I also made these cute little pies filled with the curd (and whipped cream + some sugar-free marzipan decorations):
The curd tastes really good on this succulent, slightly cake-like keto bread:
But you must be dying for the recipe by now, so, here it is:
Tips for variation
When I was making this plum curd (and experimenting with other ways to use up the huge amount of plums from our tree!), I had lots of ideas for variation on the basic recipe. For instance, you can add a stick of Ceylon cinnamon to the plums while they’re simmering. Just remove the stick right before you press the plums through that mesh strainer.
You can also use a vanilla bean in exactly the same way. Cook a sliced vanilla bean together with the plums, and remove it before straining.
There are plenty more exciting spices to use: star anise is my new favorite (I used it in my spicy keto plum jam as well). Cloves, ginger, cardamom, nutmeg, lemon peel, orange peel: any of these would provide some warmth and depth to this luscious keto plum curd.