onsen tamago

I don’t know when the obsession started, but I began dreaming about hot spring eggs (onsen tamago) a week or so ago. I blame Amy and all her wonderfully documented meals in Japan. Even more so when I discovered that it was so simple to make yourself at home. Short of a hot spring in your backyard, an onsen tamago is only ever a few short steps away (as long as you’re making rice in a rice cooker in the first place, that is).

Backtracking a bit – some of you might be wondering “What the heck is onsen tamago anyway?” The short answer is that it’s a gorgeous egg dish that’s commonly served as a breakfast item at hot springs hotels in Japan. The reason being that the temperatures of the hot springs (ie below boiling point) are perfect for poaching these eggs so lightly that they just become ethreally silky and just slide lusciously down your throat. It also works so that the yolks are set on the outside, but the whites are only loosely set and creamy. Essentially, the eggs are ‘poached’ inside the shells; when they’re ready, you crack it open into a bowl filled with a mixture of dashi, mirin and soy sauce, sprinkle over some spring onions, and slurp it all down. It’s fascinating that such a simple dish can be so satisfying (though those of you who feel squeamish at the thought of semi-raw eggs should turn away, now!).

So how do you make it? First thing would be to get the ‘broth’ ready for your egg. All I did was use a teaspoon of dashi powder dissolved in about 4 tablespoons of water, a teaspoon of mirin and a teaspoon of soy sauce. Mix together and leave to chill in the fridge until needed.

Clearly, it’s important to make sure you get the freshest eggs you can, and make sure they’re at room temperature (run under warm water if you take them straight out of the fridge and want to use immediately). Then, all you need is a rice cooker that’s just finished cooking some rice, and some kitchen paper. Because I was steaming rice for dinner anyway, this all worked out fine.

Once the rice has finished cooking, the rice cooker will automatically switch to the handy ‘keep warm’ function – which coincidentally maintains the perfect temperature for making onsen tamago. All you need to do then is wrap the egg in a layer of kitchen paper (this is just to make sure the eggs aren’t heated directly) and set it gently on top of the cooked rice. Cover, and leave to ‘cook’ for one hour. When time’s up, gently crack your egg open and let it slide into the dashi/soy sauce/mirin mixture you’ve made in advance. Sprinkle over some chopped spring onions, and, if you’re feeling particularly decadent, a few bonito flakes. Slurp it all down in one go a la prairie oysters, or eat the egg white and yolk separately in spoonfuls. The egg whites take on a super silken tofu-like texture, which is extremely yummy and even better when eaten with the broth.

Too bad I didn’t get to experience the entire egg yolk, considering I dropped it after taking the first photo on the left! I managed to salvage half. The things I do for this blog…

The much harder way to make onsen tamago is to keep a pot of warm water going at the constant temperature of 65C for 20-30 minutes while you cook the eggs, but that requires way too much patience and a thermometer (both of which I do not have). Another way, I’ve heard, was to fill a thermos full of hot water and keep the egg in it overnight, so you can have it the next morning! Not so sure about that one though, it seems like leaving a semi-warm egg overnight and then eating it seems like you’re just asking for food poisoning.