Blend spice paste ingredients with ¼ cup (60ml) water. Transfer to a bowl.
Bring 2 cups (480ml) water in a large pan to a boil. Add mackerel, lower heat to medium low and poach for 15 minutes. Remove fish when cooked. Strain liquid with a metal strainer. You should get about 1 cup (240ml) fish stock.
When fish is cool enough to handle, remove bones and flake the meat. Break into small pieces but keep some in bigger chunks.
Heat vegetable oil in a large pot and stir fry ground spice paste and kaffir lime leaves until fragrant, about 5 minutes. Add fish stock, coconut milk, and 2¼ cups (540ml) water.
Add asam gelugor and daun kesum.
Return flaked fish to the pot.
Bring soup to a gentle boil. Season with sugar and salt. Lower heat, and allow it to simmer to 10 minutes.
Cook dried thick vermicelli in boiling water for a minute. Then turn off heat and let it soak for 6 to 8 minutes until soften. Remove and drain before serving.
Place some noodles in a bowl. Top with a little julienned cucumber, pineapple, onion, red chili, mint leaves, and torch ginger (if available). Pour gravy over the noodles.
Serve immediately with hei ko (shrimp paste) and lime wedges.
Notes
** Fresh thick rice noodles should be cooked in boiling water for 1 to 2 minutes. Remove and strain before serving.