Hawaiian Butter Mochi

Before you start

Butter mochi is a Hawaii favorite: a pan of glutinous rice flour batter enriched with coconut milk, evaporated milk, eggs and butter, baked until the top is deep golden and the edges are crisp. The inside is soft, springy and chewy, somewhere between a custard and a rice cake. Mochi takes its name from the Japanese rice cake, but this oven-baked version is its own thing.

The flour matters most. It must be glutinous or sweet rice flour, sold as mochiko; regular rice flour does not turn chewy and bakes up gritty. Despite the name, glutinous rice contains no gluten. Bake it longer than looks necessary, until it is deeply browned, and cool it fully before cutting. Warm mochi is gummy and tears; cooled, it slices into clean, bouncy squares.

Ingredients

• 454 g (1 lb box, about 3 cups) glutinous rice flour (mochiko)
• 400 g (2 cups) granulated sugar
• 1 tsp baking powder
• ½ tsp fine salt
• 1 can (400 ml / 13.5 oz) full-fat coconut milk — well shaken
• 1 can (354 ml / 12 oz) evaporated milk
• 4 large eggs — room temperature
• 115 g (½ cup) unsalted butter — melted and slightly cooled
• 2 tsp vanilla extract

Method

1. Heat the oven to 175°C (350°F). Grease the pan well with butter, including the corners.
2. Whisk the rice flour, sugar, baking powder and salt in a large bowl until no lumps remain.
3. In another bowl or a large measuring jug, whisk the coconut milk, evaporated milk, eggs, melted butter and vanilla until smooth.
4. Pour the wet mixture into the dry and whisk until completely smooth and the consistency of thin pancake batter. Scrape the bowl to catch any dry pockets.
5. Pour the batter into the pan and tap it on the counter to release air bubbles.
6. Bake for 60 to 70 minutes, until the top is deep golden brown, the edges are darker and pulling away from the pan, and a toothpick in the center comes out clean. The center may puff and fall slightly as it cools.
7. Cool in the pan on a rack for at least 2 hours, until it reaches room temperature. Cut into 24 squares with a plastic knife or greased bench scraper.

Tips for success

• A plastic knife slices cooled mochi more cleanly than a metal one, which drags. A greased blade also works.
• The corner and edge pieces are the crispiest. Some cooks use a 25 x 38 cm (10 x 15 in) pan for more edges and a thinner, faster bake; check at 45 minutes.
• Buy a 1 lb box of mochiko so you can use the full box without weighing.

Substitutions

Evaporated milk

Whole milk works at the same volume. The mochi is slightly less rich and browns a little less.

Unsalted butter

Use coconut oil for a dairy-free version along with coconut milk in place of the evaporated milk; it tastes more strongly of coconut.

Vanilla extract

Add 1 tbsp matcha to the dry mix for green tea mochi, or ½ tsp coconut extract for a stronger coconut flavor.

Variations

Chocolate butter mochi

Whisk 30 g unsweetened cocoa powder into the dry ingredients and add 85 g melted dark chocolate to the wet ingredients.

Ube butter mochi

Add 2 tsp ube extract to the wet mixture for a purple, vanilla-nutty flavor.

Troubleshooting

Mochi is gummy or wet in the center

It was underbaked or cut warm. Bake until deeply browned and a toothpick comes out clean, then cool fully.

Texture is gritty and not chewy

Regular rice flour was used instead of glutinous (sweet) rice flour. Use mochiko or another sweet rice flour.

Mochi turned hard

It was refrigerated or left uncovered. Rewarm a square for 10 to 15 seconds in the microwave to soften it.

Storage

Cover leftovers and refrigerate for up to 4 days, since the batter is rich in egg and milk. Refrigeration firms the chew; rewarm squares briefly in the microwave or let them sit out for 20 minutes before eating. Do not leave them at room temperature more than 2 hours.

Safety notes

Glutinous rice flour is naturally gluten-free, but check the label for cross-contact if you are serving someone with celiac disease. Contains egg and milk. Do not taste the raw batter.