Cured egg yolks: a (successful) experiment

I’ve seen cured egg yolks growing in popularity around the internet of late, with slivers of grateable golden yolk showing up on instagram and pinterest. A quick google shows similar adaptations of eggs cured in salt and sugar showing up in Epicurious, bon appetit, America’s Test Kitchen and bloggers like Eva from Adventures in Cooking like getting in on the action.

Now, I wasn’t quite sure what the point was. Curing is a process that tends to take a long time and whilst there’s not necessarily enormous amounts of effort involved I was unsure whether the end result would actually get used or sit in the fridge until being ejected weeks later. And you should know by now how I feel about food waste. Saying that, cured egg yolks have been heralded as parmesan substitutes, are pretty cheap and easy to make, and can be stored in the fridge for up to a month. So I thought, why not?

So, what is a cured egg yolk?

Curing is not the same as pickling, so for all my British friends out there, who are envisioning a vinegary bar snack, I’m afraid this is a different thing. A cured egg yolk is a yolk that has been separated from its white before being (carefully) submerged in a mixture of salt and sugar, and occasionally herbs and spices, for a few days until the majority of the moisture has been removed. Due to osmosis the salt in the mixture will effectively suck them dry. Then to make continue to dry them out and make them firm enough to grate they are either dried in a cool oven or dehydrator, or tied in cheesecloth and left for a few more days hanging at room temperature. They will be firm while remaining pliable.

Egg yolk in hand
Egg yolks

The idea is that the richness of the egg yolk remains, but the cure also brings out sharper umami flavours that can be used to add a savoury note to various dishes. Curing is a technique that works with all egg yolks from ostrich to quail – the timings and quantities of salt and sugar will just differ. In the name of experimentation I’m using chicken eggs and the table salt and brown sugar I already had in my cupboard. In hindsight it probably would be fairer to use white sugar, as the brown sugar may add a richer more candied note, but who knows, that might be nice too.

Egg yolks about to be cured
Egg yolks on their curing mixture
Bowl of curing eggs

How do you use cured egg yolks?

Cured egg yolks are constantly likened to hard cheeses like grano padano or parmesan and as such can be used in a similar way. Grate on to pasta dishes, or use a peeler to create slivers that can be tossed through a salad. Add to risottos and sprinkle over avocado toasts.

The recipe also leaves you with leftover egg whites and possibly a broken egg yolk or two, which shouldn’t go to waste. I accidentally broke not one but two yolks in the duration of this experiment, which went onto become mayonnaise (and subsequently aioli) and the egg whites became chocolate mousse (which I was actually rather chuffed with).

Cured egg yolk out of curing mixture
Three cured egg yolks

The experiment

So the rules of the experiment were as follows: only salt and sugar was allowed in the cure. No cheating with herbs and spices to cover up any flavours I didn’t like (and it would also give me something to play with later if I liked the initial result). The proportion of salt to sugar changes from recipe to recipe, but a 1:1 ratio seems to be common. Due to using brown sugar that may have a richer effect I decided to up the salt a little in an attempt to balance things out. I chose chicken eggs as they’re readily available and a good basis for more experiments later. Finally, I decided to only cure 3 egg yolks. They are easily made in bulk and last for a long time so adding more if successful would be simple, however in the name of food waste, and remembering how the last experiment went I decided to err on the side of caution.

Cured egg yolks on a marble board

How to cure egg yolks

Ingredients:

  • 3/4 cup of salt
  • 2/3 cup of brown sugar
  • 3-5 eggs
  1. Combine the salt and sugar well and pour 1/2 to 2/3 of the mixture into the bottom of a dish around 15 cm square (or equivalent). I only cured 3 egg yolks, but this mixture should do up to 5.
  2. Make indentations in the salt mixture for where you want your egg yolks to sit. For this you can use a whole egg and just press gently onto the curing mix.
  3. Separate your eggs. Over a bowl crack your egg and gently tip the yolk from egg shell to egg shell as the egg white falls into the bowl underneath. If you find this too difficult you can also pour the egg onto your hand and strain the whites through your fingers. Once the egg white has separated transfer the yolk into one of the indentations you made in the salt and sugar. Try not to crack the egg yolk. If you do by accident, just put into a separate bowl for using later.
  4. Repeat with the remaining eggs.
  5. To cover the yolks with the remaining salt and sugar cure begin by gently sprinkling the mixture onto them – you don’t want to accidentally break a yolk at this point by rushing. Once they have a dusting covering them you can be a bit quicker with the rest.
  6. Place a marker on where each yolk is (I used peppercorns), before covering the dish and leaving to cure in the fridge for 4 days.
  7. After four days excavate the yolks from the cure by gently spooning off the excess mixture and carefully lifting each yolk out of the dish. You’ll notice that the cure now resembles wet sand due to the moisture it has drained from the egg yolks, which are now firmer, tacky and darker in colour than they were originally.
  8. You can use a pastry brush to get any remaining cure off the egg yolks, but you needn’t be too precise.
  9. Preheat the oven to about 65°C and place the egg yolks on a rack for about 1 1/2 hours. At this point the eggs will be firm yet pliable and can be stored in the fridge for up to a month once they have cooled down.

The result

Tomato pasta with cured egg shavings

Not bad. Not bad at all. The yolks don’t quite taste as I thought they might as they’re not as rich as I’d imagined. However, the salty sweet umami thing they’ve got going on does work. In a video from bon appetit, which I kinda wish I had seen before beginning my experiment, Brad tests different types of eggs against one another and duck eggs come across as richer, so maybe playing around with the duck or goose eggs would help to bring out the yolkiness more. Also, the cure is reasonably strong so I can see that playing with spices would be particularly effective, even if just whacking in a tablespoon of cracked black pepper. If you find it too strong it can also be rinsed off, leaving a more subtle flavour.

The cured egg yolks do taste great on pasta, although I’m not entirely sure if I’d use them as a substitute for parmesan – I’m probably more likely to use them in addition if completely honest. The flavour is sharp, but pretty versatile so I’ll carry on using these yolks up (hello, carbonara) and then I’ll be testing variations out. It takes about half a yolk per dish, so it won’t be long before I’ll need to whip up another batch.

Any ideas for what I should be experimenting with next month, just let me know!