Thai Fish Cakes (Tod Mun Pla)

Steps

1. Start with the syrup for the relish, since it needs to cool. In a small saucepan, combine the rice vinegar, 50 g of the sugar, the salt, and the water. Heat over medium, stirring, until the sugar dissolves, then simmer for 1 minute: the liquid turns barely syrupy. Pour it into a bowl and let it cool completely.
2. Cut the cod into 1 1/4 inch (3 cm) cubes, feeling for and removing any remaining pin bones, then pat them very dry with paper towels. Spread them on a plate and put them in the freezer for 15 to 20 minutes, until firm on the surface but not frozen, between 32 and 36°F (0 and 2°C).
3. Fold each makrut lime leaf in half and pull out the center rib. Stack the halves, roll them tightly, and cut them into hair-thin strands. Cut the long beans into 1/8 inch (3 mm) rounds.
4. Put the cold fish in the food processor bowl with the curry paste, fish sauce, 5 g of the sugar, the egg, and the cornstarch. Pulse, then process continuously for 1 to 2 minutes, scraping down the sides twice, until you have a smooth, sticky, glossy paste that turns as a single mass. Don't go past 2 minutes, or the paste will heat up.
5. Transfer the paste to a bowl. Wet your hand, lift the paste, and throw it hard against the side of the bowl, 30 to 40 times, for 2 to 3 minutes: it becomes firmer, bouncier, and holds whatever shape you give it. Fold in the beans and makrut lime, then refrigerate for 20 minutes.
6. Meanwhile, pour the oil into a wok or tall saucepan, at least 2 inches (5 cm) deep, and heat it to 350°F (175°C). Quarter the cucumber lengthwise and slice it thinly, and thinly slice the shallot and chile. Stir them into the cooled syrup. Roughly crush the peanuts and keep them separate so they stay crunchy.
7. Lightly oil your hands with a few drops of the frying oil. Take about 40 g of paste, roll it into a ball, then flatten it into a patty 2 1/2 inches (6 cm) across and 1/2 inch (1 cm) thick. Set the patties on an oiled plate; you'll get 16.
8. Slide 4 or 5 patties into the oil, away from you to avoid splashes. Fry for 3 to 4 minutes, flipping halfway: they puff up, float to the surface, and turn a deep golden brown with blistered edges. The center should reach 145°F (63°C). Keep the oil between 340 and 355°F (170 and 180°C) and let it come back up to 350°F (175°C) between batches.
9. Drain the cakes on a rack set over a sheet pan rather than on paper, where steam would soften the bottoms. They deflate a little as they cool, which is normal. Serve hot with the cucumber relish in small bowls, sprinkled with the peanuts.