Make sure you soak your peas in cold water for a few hours before preparing this dish.
Add the peas to 4 cups of water in a large dutch oven or something similar (I like caste iron for this dish). Simmer, uncovered, for about 45 minutes or until the peas are tender. Add water as needed. Drain and set aside.
Melt butter along with olive oil in the same pot. Add onion, tomatoes and chile, and saute for about 10 minutes. Add garlic, ginger, chili powder, coconut milk, and sugar and bring to a simmer. Stir in the turmeric and stock. After about a minute or two, reduce heat to low and simmer (uncovered) for about 15 minutes.
Add the peas and salt and cook for about 10 more minutes.