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A Hawaiian sheet cake made from glutinous rice flour, coconut milk and butter: chewy, dense, custardy in the middle and crisp at the edges, with no wheat in it at all. It comes out of the Japanese-American community in Hawaii, where mochiko — sweet rice flour — was a staple, and it is now a potluck fixture across the islands.
It behaves like nothing else in this folder, and the reason is the starch.
What makes it work
- Glutinous rice flour is almost pure amylopectin. Wheat starch is a mix of amylose and amylopectin, and amylose is what makes a crumb. Amylopectin gelatinises into something elastic and chewy instead — which is why this cake has no crumb structure at all and does not stale in the way a wheat cake does. Naturally gluten-free; see Gluten Free Grains.
- Mochiko specifically, not rice flour. Ordinary rice flour is a different grain and gives a gritty, sandy cake.
- A long bake at moderate heat. An hour at 175 °C. The starch needs time to gelatinise fully; underbaked butter mochi is gluey rather than chewy.
- The edges are the best part, and a metal pan gives better edges than glass.
- Cool completely before cutting. Warm, it is a pudding; cold, it is a cake.
Ingredients
One 23 × 33 cm tin. Serves 20.
- 450 g mochiko (glutinous rice flour)
- 400 g granulated sugar
- 12 g baking powder
- 4 g fine salt
- 400 ml coconut milk, full fat
- 350 ml evaporated milk
- 4 eggs
- 170 g unsalted butter, melted
- 2 tsp vanilla — see Pure vanilla extract
- 50 g desiccated coconut, to top
Method
Heat the oven to 175 °C / 350 °F. Butter a 23 × 33 cm metal tin.
Whisk the mochiko, sugar, baking powder and salt.
In another bowl whisk the coconut milk, evaporated milk, eggs, melted butter and vanilla.
Pour the wet into the dry and whisk until completely smooth — this batter is thin and pourable and cannot be overmixed, because there is no gluten to develop.
Pour into the tin and scatter the desiccated coconut over.
Bake 60–70 minutes, until the top is golden brown and set and the edges pull away slightly. A skewer will come out sticky rather than clean; that is normal.
Cool completely, at least three hours, before cutting into squares.
Notes
- It stays chewy for three days at room temperature and goes hard in the fridge — never refrigerate it. Reheat a square 15 seconds if it firms up.
- Matcha, ube, chocolate and pandan are the standard variations; add 30 g of powder and reduce the mochiko by the same.
- The same flour makes Filipino bibingka and Japanese daifuku — a good starting point for a wider look at rice flour baking.
Elsewhere on the site
Method and theory: Cake recipes · cakes · Gluten Free Grains · Coconut milk
Nearby: tres leches cake · japanese cotton cheesecake · wacky cake