Step 1

Line an 8x8-inch baking pan with plastic wrap, leaving a generous overhang on every side.

Step 2

Place 1 cup water, 3/4 cup mochiko rice flour, and 2 tablespoons of the granulated sugar in a medium microwave-safe bowl and stir with a flexible spatula until no clumps remain. Cover and microwave on high for 1 minute.

Step 3

Remove the bowl from the microwave, stir, and scrape down the sides. Microwave for 1 minute. The dough should feel supple but still sticky. If it still feels too wet, microwave for 30 seconds to 1 minute more. Let the dough cool slightly while you prepare the rice cereal mixture.

Step 4

Place the remaining 1/4 cup granulated sugar, 1/3 cup honey, 5 tablespoons unsalted butter, and 1/2 teaspoon kosher salt in a large saucepan oven. Cook over medium heat, stirring frequently, until the mixture comes to a boil, 2 to 3 minutes. Remove the pot from the heat. Add 4 cups toasted rice crisp cereal and stir until evenly coated.

Step 5

Transfer half of the mixture into the baking pan. Press down with a spatula into a flat, even layer. Transfer the mochiko dough on top and spread it evenly over the rice cereal layer. Top with the remaining rice cereal mixture and press into an even layer.

Step 6

Lightly coat your hands with butter or water. Gently press on the top of the slab with your hands to flatten into a very even layer. Wrap the overhanging plastic wrap over the slab and press down with your hands once more to flatten. Refrigerate until set, about 3 hours.

Step 7

Remove the slab from the pan, uncover, and place on a cutting board. Garnish with flaky salt and cut into 16 squares.