1. Preheat the oven to 550°. In a medium bowl, whisk together the eggs until foamy. Pour the ice water through a fine-mesh sieve and into a medium bowl. Measure out ¾ cup water and add to the eggs (discard the ice cubes). Whisk in the rice flour, zucchini, scallions and onion and then whisk in the fish sauce, yuzu and sambal.

2. In an 8-inch skillet with an oven-safe handle, melt the butter over high heat. Pour half of the batter into the skillet and swirl to create an even layer. Once the edges are set, after about 1 minute, transfer the skillet to the oven and bake until the top is golden-brown, rotating the pan midway through cooking, about 12 minutes. (For an especially browned top, adjust the oven rack to the upper-middle position and heat the broiler to high; finish the pancake under the broiler for 1 to 2 minutes.)

3. Remove the skillet from the oven and transfer the pancake to a plate. Slice into sixths. Repeat with the remaining butter and batter. Place 3 wedges on each plate and serve.