Dice onion and mince garlic cloves. Soak the dried shiitake mushrooms for half an hour in warm water. Clean the liver thoroughly under the water. Remove all of its white tendons.
Quickly roast the liver in the oven for 10 minutes at 400°F/200°C.
Slice the pork belly into small strips. When the shiitake mushrooms soften, cut them into small pieces.
Remove the roasted liver from the oven and leave it to cool.
When cooled, chop the liver into thin strips.
Soak the bread crumbs in 20 ml of fresh milk until softened. Soak the liver in the remaining milk for 15-20 minutes or longer. Afterward, take these liver pieces out and rinse them with water.
Sauté garlic and onions with butter in a hot pan until fragrant. Then, stir in pork belly and quickly sauté it for a couple of minutes. Add pork liver and continue stirring for another 2 minutes.
Season the mixture with all the spices. Sprinkle Thai basil leaves and cook for 1 minute. Drop the soaked bread crumbs into the pan.
Stir until evenly mixed, and turn off the flame.
Pulse the mixture in a food processor until smooth. Then, transfer it into a glass container.
Cover the container with aluminum foil and steam it in a steamer or regular pot. Use an amount of water equal to half the glass container. Steam for 1 hour at medium-to-low flame.
Afterward, remove the pâté and serve!