Coconut Rice Cake — Thai sweet coconut sticky rice, pressed and sliced

i. Origin & history

Glutinous rice is the everyday staple of northern and north-eastern Thailand and of Laos, steamed in woven baskets and eaten by hand with savoury food. In central Thailand it became above all a rice for sweets, and the most basic of them is khao niao mun. Khao niao means sticky rice, and mun describes the technique of working hot coconut milk into freshly steamed rice so that it is absorbed. Coconut sticky rice is often said to have been refined in the royal kitchens of the Ayutthaya and early Bangkok periods, and today it is sold at every market in Thailand.

Once made, khao niao mun is a base for a whole family of sweets. Paired with sliced ripe mango it becomes khao niao mamuang, Thailand's best-known dessert abroad. With durian it becomes khao niao thurian; topped with an egg-and-palm-sugar custard it becomes khao niao sangkhaya, using the same custard as sankaya; and wrapped round banana in leaves and steamed it becomes khao tom mud. There are even savoury-sweet toppings, such as dried shrimp and coconut.

Pressed into a tray and cut into squares, coconut sticky rice is a practical form for market sellers and for home: it travels well, holds its shape and can be eaten without a spoon. In markets it is often sold in small banana-leaf parcels or trays, topped with a thick spoon of coconut cream, a sprinkle of crisp yellow mung beans or toasted sesame.

The same idea of glutinous rice cooked in coconut milk is found right across Southeast Asia — the Filipino suman and biko, Malaysian pulut and Indonesian ketan are all relatives — but the Thai technique of steaming first and adding coconut afterwards gives a distinctively separate, glossy grain rather than a porridge-like mass.

ii. Why the rice is steamed first and soaked second

The defining method of khao niao mun is that the rice is not cooked in the coconut milk. Soaked glutinous rice is steamed on its own until tender, and only then mixed with hot, sweetened coconut milk and left covered to absorb it. Cooking the rice directly in coconut milk, as for a risotto, tends to scorch, gives an uneven texture and turns the grains mushy; steaming first cooks each grain evenly and keeps it whole.

Soaking is essential too. Glutinous rice must be soaked for at least four hours, ideally overnight, so that the grains hydrate all the way through before steaming. Unsoaked rice stays hard in the centre however long it is steamed. The soaked rice steams in about 25–30 minutes, until translucent and chewy without a chalky core.

The rice must be hot when the coconut milk goes in. Hot starch absorbs liquid readily; cooled rice firms up and resists it. The coconut milk is warmed with sugar and a surprising amount of salt until dissolved, poured over the steaming rice, stirred, and covered. After 15–20 minutes the rice has drunk in the liquid and every grain is glossy, sweet and faintly salty. This sweet-salty balance is fundamental to Thai desserts, and the salt should be clearly detectable.

The topping, hua kathi, is coconut cream thickened with a little rice flour and seasoned with sugar and more salt. It stays white and pourable and is spooned over just before serving, giving the dessert its creamy, salty finish.

iii. Ingredients

Makes 6 servings · scroll the side panel to adjust

• 400 g Thai glutinous (sticky) rice
• 400 ml coconut milk
• 100 g sugar
• 1 tsp salt
• 2 pandan leaves, knotted (optional)
• 200 ml thick coconut cream (topping)
• 2 tbsp sugar (topping)
• ½ tsp salt (topping)
• 2 tsp rice flour (topping)
• 2 tbsp toasted sesame seeds or crisp fried mung beans

Buy rice labelled glutinous or sweet rice, ideally Thai long-grain glutinous rice; the opaque, chalk-white grains look very different from jasmine rice, which will not work. Use full-fat coconut milk with no added thickeners if you can find it; for the topping, use the thick cream that rises to the top of a can. Pandan leaves, steeped in the coconut milk, add a gentle vanilla-like fragrance. Toppings vary: crisp yellow mung beans (sold ready-fried in Thai shops) or toasted sesame add crunch.

iv. Method

1. Rinse the rice in several changes of water until the water runs nearly clear. Cover with plenty of cold water and soak for at least 4 hours, or overnight.
2. Drain the rice. Line a steamer basket with muslin or a clean cloth, spread the rice in an even layer and steam over boiling water for 25–30 minutes, turning it over halfway, until the grains are translucent and chewy with no hard centre.
3. Meanwhile, warm the coconut milk, sugar, salt and pandan in a pan, stirring, until the sugar dissolves and the mixture is hot but not boiling. Remove the pandan.
4. Tip the hot rice into a bowl, pour over the hot coconut milk and stir gently to coat every grain. Cover tightly and leave for 20 minutes, until the liquid is absorbed and the rice is glossy.
5. Line a 20 cm square tin with baking paper or banana leaf. Press the rice in firmly and evenly with a damp spatula or the back of a spoon. Leave to cool and set for 30 minutes.
6. For the topping, whisk the coconut cream, sugar, salt and rice flour in a small pan. Heat gently, stirring, until it just simmers and thickens to a pouring cream, about 2–3 minutes. Cool.
7. Turn out the rice cake and cut into squares with a wet knife. Spoon over a little topping and scatter with sesame seeds or crisp mung beans just before serving.

v. Tips & common mistakes

• Soak the rice long enough. Four hours is the minimum; under-soaked rice has a hard centre however long you steam it.
• Steam, do not boil. Boiled glutinous rice turns to a sticky paste. Steaming keeps the grains whole.
• Add the coconut milk while the rice is hot. Cold rice resists the liquid and stays dry and firm.
• Season with real salt. Thai coconut desserts are distinctly salty-sweet. Too little salt makes the cake taste flat and cloying.
• Do not boil the coconut milk hard. It can split and turn oily. Heat it just until the sugar dissolves.
• Never refrigerate. Sticky rice hardens in the cold. Keep it covered at room temperature and eat the same day.

vi. Variations

Serve the squares with ripe, sliced mango for khao niao mamuang, or with durian for sticky rice with durian. Khao niao dam uses black glutinous rice for a purple, nutty version. Tinting the coconut milk with butterfly pea flowers gives a striking blue rice, and pandan extract gives green. Topping it with steamed custard gives khao niao sangkhaya.

Across the region, compare the Filipino suman and bibingka, and Malaysia's two-layered seri muka, which pairs pressed glutinous rice with a pandan custard. Within Thai sweets, khao tom mud wraps the same rice round banana.

vii. Serving & storage

Coconut rice cake is eaten at room temperature, as a snack, a breakfast or a dessert after a meal. With mango it is a hot-season favourite, in April and May when Thai mangoes are at their peak. On its own it is often sold wrapped in banana leaf for eating on the go.

It is best eaten the day it is made and kept covered at room temperature. Sticky rice hardens quickly in the fridge as the starch retrogrades; if you must store it overnight, wrap it tightly and re-steam or microwave it briefly under a damp towel to soften it. Keep the topping separately in the fridge for up to 2 days. It does not freeze well.

ix. More from Thai

• Sticky Rice with Durian — coconut rice and durian
• Khao Tom Mud — banana sticky rice parcels
• Sankaya — Thai coconut custard
• Khanom Krok — coconut-rice pancakes
• Suman — Filipino rice in banana leaf
• Seri Muka — pandan custard rice cake