Separate and collect the meat and skin, keeping the head and bones for preparing the savory broth. Set aside.
Prepare the grill-charred ingredients:
On a charcoal grill or in a pan, char roast the yellow and apple eggplants.
Allow to cool, peel and set aside.
On a cutting board and using a knife, mince the eggplants together with the grilled catfish meat to a fine consistency. Set aside.
Prepare the crispy catfish skin:
Fry the skin on very low heat until crispy. Set aside.
Prepare the crispy ingredients (เครื่องหมี่; khreuuang mee):
In a mortar and pestle, pound unpeeled Thai garlic. Use just enough force to mash the garlic cloves, leaving the peels intact. Do not try to make a smooth paste. The peels will crisp fry and add a desired textural element.
To a cold wok, add all the garlic, cover with cold oil, and turn the heat to medium-low. Stir constantly in one direction only until the garlic is very light golden in color.
Add the dried fish scales.
Strain the oil and set it aside.
Fry the dried bird’s eye chilies, starting with cold oil, until crisp and shiny. Set aside.
Prepare the savory paste:
An overview of the savory paste ingredients.
In a mortar and pestle, pound the lemongrass, shallots, and garlic into a fine paste. Add Northern-style fermented shrimp paste and combine well.
Fry the paste with some of the residual garlic oil until fragrant. Set aside.
Prepare the savory broth (น้ำนัว; naam nuaa):
In a pot, bring water, seasoned fermented fish sauce, and lemongrass to a strong boil. Add the head and bones of the grilled catfish. Simmer on low heat and reduce to a concentrated stock. Strain and set aside.
Prepare the herbs:
Thinly slice the spring onion. Set aside.
Roughly chop the coriander leaves. Set aside.
Slice the sawtooth coriander into wide juliennes. Set aside.
Combine the laap:
In a mixing bowl, combine the grilled catfish meat with the grilled eggplants and only half the amount of the fried savory paste. It is important not to add all the savory paste at once, to ensure that the dish is not over-salty when wetting the fish mixture with the broth.
Using your hand, mix and squeeze the fish meat to allow the meat to blend with the paste and eggplants – and also to ensure that there are no remaining fish bones.
Gradually add savory broth and the remaining savory paste until the catfish meat is moist and soft.
At this stage, use just enough paste and broth to produce an under-seasoned but well-moistened fish.
Season with phrik laap.
Taste and adjust the seasoning to your liking. Adjust spiciness with ground dried chilies; adjust numbness with makwen; adjust saltiness with either fish sauce or makwen-infused fish sauce; and adjust the spice aroma with the laap spices mix.
Adjust saltiness.
Adjust spice aroma.
Adjust numbness.
When you are satisfied with the seasoning, add the herbs and mix. Keep some herbs to garnish the dish.
Garnish with fried chilies, crispy ingredients, and the remaining herbs. Serve alongside the crispy fish skin and phak gap laap (ผักกับลาบ) – fresh herbs and vegetables.