Ube Ice Cream — Filipino purple yam ice cream

i. Origin & history

Ube is a tropical yam native to Southeast Asia that has been grown in the Philippines for centuries. Its flesh ranges from lilac to deep violet, and in Filipino cooking it is used almost entirely for sweets: boiled, mashed and cooked down with milk, sugar and butter into ube halaya, a rich jam that is eaten on its own, spread on bread and used to flavour cakes, breads, pastries and ice cream. Bohol and Benguet are among the provinces known for it.

Ube is often confused with two other purple tubers. Taro (gabi) has pale flesh flecked with purple and a starchy, nutty flavour; many 'taro' bubble teas outside Asia are coloured purple to look like ube. Okinawan purple sweet potato (Ipomoea batatas) has a similar colour but a different texture and flavour. True ube is a yam, moister and more delicately sweet.

Ice cream arrived in the Philippines in the colonial era, and Filipinos quickly made it their own with local flavours. Street vendors sell sorbetes — affectionately called 'dirty ice cream' because it is sold from carts — in flavours such as ube, cheese, mango and queso. Ube was also adopted by Filipino dairy brands and ice cream parlours through the twentieth century, and it became the standard topping for halo-halo.

In recent decades ube has become a global ambassador for Filipino food. Its photogenic purple colour helped it spread through cafés and social media around the world, appearing in doughnuts, lattes, cheesecakes and croissants. Ube ice cream remains the simplest and most popular way to taste it.

ii. Where the purple comes from

Ube's colour comes from anthocyanins, the same water-soluble pigments that colour blueberries and red cabbage. Anthocyanins are sensitive to pH: they are reddish-purple in acidic conditions and shift towards blue and even green in alkaline ones. That is why ube desserts sometimes turn greyish or blue-green when baked with too much baking soda, and why a little acidity keeps the purple vivid. In ice cream the base is close to neutral, which gives a soft lilac colour.

Natural ube halaya gives a lovely flavour but a relatively muted colour, which is why most Filipino recipes add a little ube extract. Ube extract is a concentrated flavouring, usually with added colour, that gives the bright violet most people associate with ube ice cream. Using both gives the best balance of real flavour and strong colour.

The base here is a custard: milk, cream and coconut milk heated and thickened with egg yolks. The yolks add richness and act as emulsifiers, coating the water and fat so that ice crystals stay small and the texture smooth. The ube halaya, being dense with starch and sugar, also helps keep the ice cream soft and scoopable.

The custard must be cooked gently to about 80 °C, until it coats the back of a spoon, then chilled thoroughly before churning. A cold base churns faster and produces smaller ice crystals, giving a creamier result.

iii. Ingredients

Makes 8 servings · scroll the side panel to adjust

• 300 ml whole milk
• 300 ml double cream
• 150 ml coconut milk
• 120 g caster sugar
• 4 large egg yolks
• 250 g ube halaya (purple yam jam)
• 1 tsp ube extract
• 1 pinch salt
• 60 g macapuno strings, chopped (optional)

Ube halaya is sold in jars in Filipino shops, or can be made from frozen grated ube cooked with condensed milk and butter. Ube extract is sold in small bottles; brands vary in strength, so add it gradually. Powdered ube (dehydrated ube) can be rehydrated and used instead of halaya. Coconut milk gives a subtle tropical note; it can be replaced with more milk. Macapuno, a soft, jelly-like coconut, makes a classic mix-in.

iv. Method

1. Heat the milk, cream, coconut milk and half the sugar in a pan until steaming, but not boiling.
2. Whisk the egg yolks with the remaining sugar until pale. Slowly pour in about a third of the hot milk, whisking constantly, then pour the mixture back into the pan.
3. Cook over low heat, stirring constantly with a spatula, for 5–8 minutes, until the custard thickens enough to coat the back of a spoon (about 80 °C). Do not let it boil.
4. Remove from the heat and whisk in the ube halaya, ube extract and salt until smooth. Blend with a stick blender for the smoothest result, then strain.
5. Cool, then cover and chill for at least 4 hours, or overnight, until very cold.
6. Churn in an ice-cream machine according to the manufacturer's instructions, usually 20–30 minutes, until thick. Fold in macapuno, if using, at the end.
7. Transfer to a chilled container, press baking paper onto the surface and freeze for at least 3 hours until firm enough to scoop.

v. Tips & common mistakes

• Cook the custard gently. Boiling scrambles the yolks; take it off as soon as it coats a spoon.
• Blend in the halaya. Ube jam is thick and can leave lumps; a stick blender makes the base smooth.
• Add extract gradually. Extracts vary widely in strength, and too much gives an artificial taste.
• Chill the base thoroughly. A warm base churns slowly and makes icy ice cream.
• Do not confuse ube with taro. Taro has a different flavour and will not give the same colour.
• Soften before scooping. Leave the ice cream out for 5 minutes before serving.

vi. Variations

Ube macapuno ice cream is a Filipino classic. A no-churn version folds ube halaya and condensed milk into whipped cream and freezes it. Vegan ube ice cream uses coconut cream and coconut milk with no eggs. Ube cheese ice cream adds grated cheese for a sweet-salty Filipino twist.

Ube ice cream is essential in halo-halo and pairs well with turon and banana lumpia. Ube also appears in sapin-sapin. For other Asian ice creams, try black sesame ice cream, hojicha ice cream and durian ice cream.

vii. Serving & storage

Serve ube ice cream in scoops on its own, in a cone, on top of halo-halo, or alongside warm desserts such as turon, bibingka or banana lumpia. In the Philippines it is also eaten sandwiched in a soft bread roll, the street-food 'ice cream sandwich' of sorbetes vendors.

Keep in an airtight container in the freezer for up to 2 weeks, with baking paper pressed onto the surface to prevent ice crystals. The flavour and texture are best within the first week. The custard base can be made up to 2 days ahead and kept in the fridge before churning.

ix. More from Filipino

• Halo-Halo — Filipino shaved ice
• Sapin-Sapin — layered rice cake
• Turon — caramel banana rolls
• Buko Pandan — coconut and pandan jelly
• Black Sesame Ice Cream — nutty Asian ice cream
• Durian Ice Cream — king of fruits ice cream