Mochi Ice Cream — ice cream wrapped in soft mochi

i. Origin & history

The idea is a natural extension of daifuku, the classic Japanese sweet of mochi wrapped around red-bean paste. Replacing the bean paste with ice cream required one technical change: a mochi that would not freeze hard. In Japan, the confectionery company Lotte launched Yukimi Daifuku ('snow-viewing daifuku') in 1981 — two small rounds of vanilla ice cream in soft mochi, sold in a pair — and it remains one of Japan's best-known ice-cream products.

The version familiar in the West came from Mikawaya, a Japanese confectionery shop founded in Los Angeles's Little Tokyo in the early twentieth century. Frances Hashimoto, who ran the business, and her husband Joel Friedman are credited with developing bite-sized mochi ice cream for the American market in the early 1990s, and their product spread through supermarkets in Hawaii and California before reaching the rest of the United States and beyond.

Since then mochi ice cream has become a global supermarket and restaurant dessert, with flavours from green tea and mango to cookies-and-cream. Several brands now sell it frozen in boxes, and it is a common dessert in Japanese and sushi restaurants outside Japan.

In Japan, ice-cream daifuku is one of many crossovers between wagashi and Western frozen desserts, alongside monaka ice-cream wafers and kakigori with soft-serve.

ii. Why the mochi stays soft in the freezer

Ordinary mochi freezes rock-hard. The water in it turns to ice, and the starch firms through retrogradation. For mochi ice cream, the dough must stay pliable at about −18 °C, and the solution is sugar. A high proportion of sugar, and especially a liquid sugar such as corn syrup or mizuame, lowers the freezing point of the water in the dough and binds it so less ice forms. Sugar also slows the starch's tendency to harden.

The result is mochi that is firm but still chewy straight from the freezer and softens to the ideal texture after a few minutes at room temperature. Commercial producers fine-tune this with starch syrups and other ingredients; at home, sugar plus a spoonful of corn syrup gets very close.

Assembly is a race against temperature. The ice cream must be scooped and frozen hard in advance, and the mochi must be cool enough not to melt it but still warm enough to stretch. A practical home trick is to line a small cup or muffin tin with cling film, lay a disc of mochi in it, drop in a frozen scoop of ice cream and twist the film closed: the cup holds the shape, the film seals the seam and the finished ball goes straight back in the freezer.

The starch dusting keeps the sticky dough from sticking to everything, but excess starch tastes chalky, so it is brushed off before wrapping.

iii. Ingredients

Makes 10 servings · scroll the side panel to adjust

• 500 ml good ice cream (vanilla, matcha, strawberry or mango)
• 120 g shiratamako or mochiko (glutinous-rice flour)
• 60 g caster sugar
• 1 tbsp light corn syrup or mizuame
• 150 ml water
• 1 tsp matcha or a drop of food colouring (optional)
• 50 g potato starch or cornflour, for dusting

Choose a dense, premium ice cream; light, airy ice creams melt quickly during wrapping. Shiratamako gives the smoothest, stretchiest mochi; mochiko works well and is easier to find. The corn syrup or Japanese mizuame helps the mochi stay soft in the freezer; golden syrup works at a pinch. Colour or flavour the mochi to match the ice cream — matcha for green tea, a little strawberry powder for pink. Cornflour is the usual dusting outside Japan; potato starch is the Japanese standard.

iv. Method

1. Line a small tray with baking paper. Scoop the ice cream into 10 balls of about 35 g with a small scoop and freeze for at least 2 hours, until very hard.
2. Whisk the rice flour, sugar, corn syrup, water and matcha or colouring, if using, in a microwave-safe bowl until smooth.
3. Cover loosely and microwave on full power for 1 minute, stir with a wet spatula, then 1 minute more and stir, then a final 30 seconds, until translucent, glossy and stretchy.
4. Tip onto a tray dusted with starch, dust the top and roll it out to about 3 mm thick. Leave to cool for 5 minutes, then chill in the fridge for 15 minutes so it is cool but still pliable.
5. Cut 10 rounds with a 9–10 cm cutter. Brush off excess starch. Line a small cup or muffin cup with cling film.
6. Working one at a time, lay a mochi round in the lined cup, drop in a frozen ice-cream ball, and quickly pull the mochi up around it, pinching to seal. Twist the cling film closed and return to the freezer immediately.
7. Freeze the wrapped balls for at least 1 hour. Before serving, unwrap and leave at room temperature for 3–5 minutes to soften.

v. Tips & common mistakes

• Freeze the ice cream very hard. Soft scoops melt against the mochi and leak through the seam.
• Cool the mochi before wrapping. Warm mochi melts the ice cream; chilled mochi stretches without tearing.
• Work one at a time. Keep the ice-cream balls in the freezer and take them out individually.
• Do not skip the sugar or syrup. They are what stop the mochi freezing hard.
• Use cling film to seal. Twisting the film closed seals the seam and shapes a neat ball.
• Let them soften before eating. A few minutes at room temperature brings back the chewy texture.

vi. Variations

Classic flavours include vanilla, green tea, strawberry, mango and red bean. Homemade black sesame ice cream, hojicha ice cream or ube ice cream make excellent fillings. For a daifuku-style version, put a teaspoon of red-bean paste on top of the ice cream before wrapping. Rolled in kinako or cocoa instead of starch, the mochi takes on extra flavour.

For mochi in its other forms, see plain mochi, daifuku and red bean mochi. Other ice-cream treats from Asia include monaka ice-cream sandwiches and Malaysian durian ice cream.

vii. Serving & storage

Serve mochi ice cream as a dessert or snack, two or three per person, after letting it soften for a few minutes. Eat it with your fingers, in two or three bites, or cut it in half to show the centre.

Wrapped individually in cling film and stored in an airtight box, homemade mochi ice cream keeps for up to a week in the freezer. After that the mochi slowly dries and hardens and the ice cream can develop ice crystals. Do not refreeze if the ice cream has melted.

ix. More from Japanese

• Daifuku — mochi with bean paste
• Mochi — the pounded rice cake
• Monaka — crisp wafer sweets
• Hojicha Ice Cream — roasted-tea ice cream
• Black Sesame Ice Cream — nutty sesame ice
• Kakigori — Japanese shaved ice