Ambulthiyal paste is a traditional Sri Lankan spice blend used to create the popular dish, Fish Ambul Thiyal. It's a flavorful paste made primarily from Garcinia (also known as Goraka or Kudam Puli) along with other spices like pepper, tamarind, garlic, ginger, chili, coriander, cumin, turmeric, and cloves according to MA's Kitchen. The paste is used to marinate fish, typically tuna, before it's cooked in a clay pot or oven, resulting in a distinctive sour and spicy flavor.