Heat a large pot over medium heat and add the curry paste.
Add the meat and brown on all sides.
Pour in the coconut milk and stir well.
Add the sliced onion and diced potatoes.
Reduce heat and let simmer for 30 minutes.
Stir in the fish sauce, brown sugar, and tamarind paste.
Cook for an additional 15 minutes until the potatoes are tender.
Add the roasted peanuts and mix thoroughly.
Garnish with fresh cilantro before serving.