Cut the lamb shoulder into 2-inch cubes and set aside.

In a large bowl, whisk together the soy sauce, fish sauce, lime juice, salt, pepper, and bay leaves. Add lamb, mixing well to coat, and marinate in refrigerator for 30 minutes.

Dice onions, carrots, and potatoes into large pieces, 1–2 inches, and place in a bowl of water to prevent oxidation; strain when ready to use. Crush the tomatoes by hand, breaking them apart for cooking. 

Preheat oven to 300° F.

Heat a large sauté pan over medium-high heat and add enough oil to coat the pan. Sear the lamb in batches until golden brown on all sides while keeping the center raw. Repeat until all lamb is seared. Transfer lamb to a Dutch oven.

Prepare braising liquid in the same pan the lamb was seared in by lightly sautéing the onions, carrots, and potatoes until golden brown. Add tomato paste and caramelize with the vegetables. Add crushed tomato and simmer for 5 minutes.

Add lamb to the braising liquid. If the lamb is not fully submerged, add water to cover it.

Cover pot and bake at 300° until meat is tender, about 2 hours.

Stir in peas just before serving.