Rinse the Long-grain rice until the water runs clear. Meanwhile steep the Dried butterfly pea flowers in hot Water for 10–15 minutes to extract a deep blue dye; strain and reserve the liquid. Cook the rice with the butterfly pea infusion, a couple of bruised Pandan leaves, a Lemongrass stalk tied in a knot, and a pinch of Salt until light and fluffy; set aside to cool and take on the blue hue.
Make the toasted coconut (serunding kelapa): heat a little Cooking oil in a wide pan, add thinly sliced Shallots and minced Garlic cloves and sauté until fragrant. Add grated Coconut, a sprinkle of Ground turmeric, grated Fresh ginger and finely chopped Galangal, plus crushed Dried red chilies and a spoonful of melted Gula melaka (palm sugar). Stir over medium heat until the coconut is dry and lightly browned; season with a little Salt and set aside.
Prepare a spicy sambal: briefly toast and rehydrate Red chilies (or use fresh), then pound or blitz them with a small piece of Belacan (shrimp paste), a handful of sliced Shallots and a clove of Garlic cloves until coarse. Fry the paste in oil until fragrant, adjust with a pinch of Sugar and Salt to balance, and set aside.
Make the tangy dipping sauce: finely slice Shallots and minced Bird's eye chilies, then mix with Budu (fermented anchovy sauce), a splash of Lime juice and a little Sugar to taste; add a squeeze of fresh Limes if you like extra brightness.
Prepare the raw and fresh elements: thinly slice Cucumber, trim and cut Long beans into bite-sized pieces, rinse Bean sprouts, and finely shred Green cabbage. Thinly slice the Torch ginger bud and finely shred or tear the Kaffir lime leaves, then toss together with torn Vietnamese mint (daun kesum) and Thai basil leaves. Reserve some chopped Bird's eye chilies for extra heat at the table.
Cook the fish: season the Mackerel (ikan kembung) with a little Salt and char on a hot grill or in a skillet with a drizzle of oil until skin is crisp and flesh flakes easily; flake into large pieces.
Warm the rice slightly if needed, then assemble: mound a portion of blue rice on each plate, surround with the shredded vegetables and herbs, spoon over the toasted Coconut mixture and a dab of sambal, and top with flaked Mackerel (ikan kembung).
Finish and serve: halve the Salted duck eggs and arrange on the side with crunchy Keropok ikan (fish crackers) and extra wedges of Limes for squeezing. Let everyone add the Budu (fermented anchovy sauce) dip, more sambal or chopped Bird's eye chilies to taste.
