3 layer pork is a common ingredient in Thai food. On this site, I usually translate it to 'pork with fat and rind' in recipes. Here I've made tom-yum out of it, cook the soup long and slow so that the pork is good and soft.

Ingredients
300 gms Three Layer Pork
5-8 Chillies
2 Garlic Cloves
10 gms Red Onion
10 gms Chopped Galangal Root
10 gms Chopped Lemon Grass
2-4 Kaffir Leaves
4 Tablespoons Lemon Juice
5 Tablespoons Fish Sauce
1 Teaspoon Salt
10 gms Chopped Coriander Leaves
400 ml Water

Preparation
1. Peel and chop the onion and garlic.
2. Into a large saucepan, put the water, galangal, lemon grass, onion and salt. Bring to the boil.
3. Cut the 3 layer pork into 5cm pieces, and add to the boiling soup.
4. Simmer for 30 minutes to 1 hour until the pork is soft.
5. Add all the remaining ingredients and simmer for 5 more minutes.
6. Serve with rice, or eat on it's own.