How to Make It
In a large bowl, cover the salt cod with cold water and soak in the refrigerator for 24 hours, changing the water at least three times. Drain and pat dry. Slice the fish across the grain and then tear it into rough 1/2-inch shreds. In a medium bowl, combine the fish with the lime leaves and brown sugar and set aside.
Meanwhile, soak the chiles in the boiling water until softened, about 15 minutes. Drain the chiles and transfer them to a food processor along with the chopped cilantro, ginger, turmeric, coriander, allspice, nutmeg, almonds, shrimp paste and shallots. Pulse the spice mixture until chopped, then puree the spice paste until smooth.
In a large nonstick skillet, heat the 2 tablespoons of oil and add the spice paste. Cook over moderately high heat, stirring frequently, until dry, about 10 minutes. Let cool completely. Stir the spice paste, egg, egg yolk and coconut milk into the fish until evenly combined.
Light a hardwood charcoal or gas grill. Cut the fibrous string off the edge of each banana leaf and reserve. On a work surface, brush half of the banana leaves with oil. Spoon half of the fish mixture onto the leaves and fold them up like envelopes to enclose the filling. Brush the packets with oil. Using half of the reserved banana strings, tie up the packets. Repeat with the remaining leaves, filling and strings.
When the temperature reaches 350°, arrange the packets on the grate over the heat source and grill, covered, for about 25 minutes, until they are fragrant and feel slightly firm to the touch. Serve the packets with cilantro sprigs, lime wedges and hot sauce.