Butter mochi

What it is

Butter mochi is a baked dessert made from mochiko, which is sweet or glutinous rice flour, mixed with coconut milk, butter, sugar, and eggs, then baked until golden. It comes out dense and chewy in the middle with slightly crisp edges, and you cut it into squares. It is not fussy, there is no dough to pound or steam like regular mochi. You just mix and bake.

A short history

Nobody knows exactly who made the first butter mochi, but it is a true melting-pot dessert from the plantation era. It brings together three traditions that all landed in Hawaii: Japanese mochi-making with sweet rice flour, Portuguese butter-and-egg baking, and the Filipino coconut rice cake called bibingka. Those threads got folded into one easy pan, and recipes for it turn up in handwritten community cookbooks all over the islands going back generations.

How to make it at home

The one rule that matters: let it cool all the way before you cut it. Warm butter mochi is gummy, but once it sets up it slices into clean, chewy squares.

Getting the texture right

Butter mochi should be chewy and dense with a thin crisp top and edges you fight over. When it goes wrong it is either gummy or dry, and both are avoidable.

Use mochiko, sweet rice flour, and nothing else. The box most people know is Koda Farms Blue Star mochiko. Regular rice flour is not the same thing and will not go chewy, and neither will wheat flour. This is the one ingredient with no substitute.

Do not overmix. Whisk until the batter is just smooth. It should be thin, closer to pancake batter than cake batter, and that is correct. Beating air into it gives you a cakier, drier result.

Bake it long enough. An hour or so at 350F, until the top is deep golden brown and the edges pull back from the pan. Butter mochi is meant to go dark on top. Pulling it at pale gold is what leaves the middle gummy. A toothpick is not much help here since it comes out sticky either way. Go by color and by the edges.

Then let it cool completely, and I mean completely, at least two hours and preferably longer. This is the rule that matters most. Warm butter mochi is a gummy mess that tears when you cut it. The same pan, fully cool, slices into clean chewy squares. If you cut in early you will think you failed when you only got impatient.

Ways to change it up

The base recipe takes additions well, and every family has a version they bring to potlucks.

Chocolate butter mochi is the most common, made by whisking cocoa powder into the batter or scattering chocolate chips over the top before baking. The chips sink partway and leave a marbled layer.

Ube butter mochi, made with purple yam extract or ube halaya, turns the pan a startling violet and adds a mellow vanilla-nutty flavor. It is everywhere in Hawaii and the Philippines now.

Matcha, black sesame, pandan, and poi all work the same way, stirred into the batter for color and flavor. Poi butter mochi is a genuinely local move worth trying if you can get poi.

Toasted coconut or sesame seeds scattered over the top before baking add crunch against the chew. Some people pour a thin layer of coconut milk over the surface partway through baking for a custardy top, a style called custard mochi.

Storing it

Keep butter mochi at room temperature, covered, and eat it within two or three days. It is best on day one and still good on day two.

Do not refrigerate it. Cold makes mochiko firm up hard and the chew turns tough. If it has been in the fridge, let the squares come back to room temperature, or give one about ten seconds in the microwave.

It freezes better than it refrigerates. Wrap individual squares and freeze up to a month, then thaw on the counter.

Questions I get

Can I halve the recipe?

Yes. Use an 8x8 pan and start checking around forty minutes.

Can I use light coconut milk?

You can, but the fat is doing real work for richness and chew. Full fat canned is the way.

Is this the same as regular mochi?

No. Regular mochi is steamed and pounded from glutinous rice into a dough. Butter mochi is a baked batter that happens to use the same rice flour, which is why it needs no pounding and no special equipment.

Why did the middle sink?

Usually underbaking, sometimes an oven running cool. A slight dip is normal and does not hurt anything.

What pan should I use?

A metal 9x13 is what the recipe is built for. Glass works but conducts heat differently, so add ten minutes and watch the color. Line it with parchment or butter it well, because the sugar in the batter makes it stick hard.

How big should I cut the squares?

Small. It is dense and rich, so inch-and-a-half squares are about right, which gets you around forty pieces from a 9x13. That is why it is such a good potluck pan, it goes a long way.

Bring a pan to your next potluck with some spam musubi, or see the rest of the Hawaiian favorites.