Tender and chewy, this big-batch dessert — as comforting as cake and as fun as bar cookies — is always a hit at parties. Mochiko, sweet rice flour, not only gives it its distinctive marshmallow-like softness, but it also lends a natural sweetness. This version of butter mochi uses only coconut milk for its richness and subtle nutty taste, but you can substitute equivalent amounts of whole milk, evaporated milk or a combination of those liquids. Butter mochi develops a crackly top that stays crunchy the day it’s baked, making it a delicious dessert to eat without adornment. But, if you’d like more crunch, you can sprinkle dried shredded coconut evenly over the top before baking, or, for a tangy, colorful top, you can coat it with the passion fruit glaze below.
Ingredients for the mochi:
• 6 tablespoons/84 grams unsalted butter, melted and cooled, plus more for greasing the pan
• 3 cups/453 grams mochiko (sweet rice flour), like Blue Star brand
• 2 teaspoons baking powder
• 1/2 teaspoon fine sea salt
• 4 large eggs
• 2 cups/416 grams granulated sugar
• 2 (13.5-ounce) cans unsweetened coconut milk (scant 3 1/2 cups)
• 1 tablespoon pure vanilla extract
Ingredients for the passion fruit glaze (optional):
• 1 1/2 packed cups/219 grams powdered sugar
• 2 to 4 tablespoons passion fruit pulp or purée (see Tip)
• Pink or red food coloring (optional)
Make the mochi: Heat the oven to 350 degrees. Lightly butter a 9-by-13-inch cake pan, then line the bottom and sides with parchment paper.
Whisk the mochiko, baking powder and salt in a medium bowl. Prepare the batter in a stand mixer or in a large bowl with an electric hand mixer or whisk: Whisk the eggs and sugar until pale yellow and thick. Continue whisking while pouring in the coconut milk, then the butter and vanilla. Continue whisking while gradually adding the mochiko mixture. Whisk until the batter is completely smooth. Pour into the prepared pan, then tap it against the counter to get rid of any air bubbles.
Bake until golden brown and crackly, 1 hour 15 minutes to 1 1/2 hours. When you press the center, it should bounce back but not indent at all. Cool com pletely in the pan on a wire rack. Use the parchment paper to slide the cooled mochi out of the pan.
The mochi is delicious plain, but you can add a glaze if you’d like: Mix the powdered sugar with 2 tablespoons passion fruit pulp until smooth. It should be thick but drippy. If needed, add another 1 to 2 tablespoons pulp. If you’d like to create an ombré or sunset effect, scrape some into another bowl or multiple bowls and tint with food coloring. Spread the glaze evenly over the mochi, in stripes if you’d like, and let stand until set.
Cut the mochi into squares or bars. Serve immediately, or keep in an airtight container at room temperature for up to 3 days.
Total time: 2 hours, plus cooling; makes 1 (9-by-13-inch) cake.
You can buy pure passion fruit purée from specialty markets and some grocery stores in the frozen fruit section. If you can’t find the fruit or purée, you can substitute passion fruit juice or nectar, but it will be much sweeter. To prepare passion fruit pulp from fresh fruit, halve 2 fruits and scrape the pulp into a small microwave-safe bowl or saucepan. Warm by microwaving for 15 seconds or heating on low until loose and runny. Press through a sieve to extract the pulp from the seeds.