KUALA LUMPUR, Oct 10 — One of my favourite discoveries during my visit to Seoul many years ago was a seasonal Korean café beverage called goguma latte (고구마 라떼).

Goguma (Korean for sweet potato) is especially popular during the colder months. Roasted sweet potatoes are sold as a winter snack while cafés have creatively transformed the humble tuber into the aforementioned drink.

Essentially steamed sweet potato blended with milk or soy milk, goguma latte is naturally sweet and comforting.

I’ve decided to put my own spin on this, albeit via a slightly different route. Instead of dairy milk, how about fresh, homemade soy milk?

The soy milk (known as doujiang in Mandarin) provides a familiar nutty flavour and naturally creamy body, which matches the mellow sweetness of the sweet potatoes perfectly.

Then there is the luxurious, lavender hue of the sweet potato soy milk (I’ve used purple sweet potatoes specifically for this effect), which simply whispers “cosy”, no?

SWEET POTATO SOY MILK

There are, naturally, more straightforward ways to make soy milk. So consider my approach more of an infusion... or fusion, as it were.

Even then, most recipes suggest blending the soy milk with the additional ingredient. This is easier, of course, but I find the result a tad clumpy as all the fibre is still retained in the blended milk.

How I do this differently is to blend the soaked raw soybeans with the cooked sweet potato before straining everything together. 

Yes, this is an extra step but it means the finished sweet potato soy milk is silky smooth and creamy without any sludge.

Speaking of “sludge”, let’s not forget the leftover pulp. Don’t throw it away!

Because the soy beans and sweet potato are blended together, the douzha (literally “bean dregs” in Mandarin) is highly nutritious. Plenty of soy protein and fibre from the sweet potatoes.

Me, I like stirring the douzha into my morning oats as it cooks (the soybean pulp is still raw, remember, so you still have to cook it). It thickens the oats naturally and adds a mild sweet potato flavour.

Note that I’ve added no sugar as the natural sugars and starches from the sweet potato give the blended soy milk a gentler, less cloying sweetness.

Ingredients

100 g dried organic soybeans

2 medium purple sweet potatoes

1.2 litres filtered water

Method

Rinse the dried organic soybeans thoroughly. Place them in a large bowl and cover with plenty of water.

Soak the beans overnight until fully rehydrated. Drain and rinse well.

Steam the sweet potatoes for about 12 to 15 minutes, or until a fork slides easily through their centres. Allow it to cool slightly.

Transfer the soaked soybeans and steamed sweet potatoes to a blender. Pour in the filtered water and blend on high for about 2 minutes, or until the mixture is smooth and milky.

Drape a muslin cloth or cheesecloth over a large cooking pot. Pour the blended mixture into the cloth.

Collecting the ends of the cloth together, squeeze firmly to extract as much of the liquid as possible. Continue squeezing until the pulp remaining in the cloth feels relatively dry.

Place the pot over medium-low heat. Stir continuously, making sure to scrape the bottom of the pot to prevent the sweet potato starch from settling and burning.

Bring the liquid to a gentle simmer. Once simmering, reduce the heat to low and cook for 15 minutes, stirring regularly. This cooks the soybeans thoroughly and removes any raw bean flavour.

Remove from the heat and pour directly into cups. Best served warm.

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