If pressure cooking, place the black eyed peas and collard greens in the pressure cooker and cook until tender. Took me about 10 minutes on a medium-low flame after reaching pressure.
In a large saucepan, heat the oil and add the onions.
Saute until they begin to brown, about 3-5 minutes, then add in the sweet potatoes and some salt and stir well.
Cover and cook on a medium flame for about five minutes, then add the cooked black eyed peas and collards. If using spinach or another green, add now. Add the curry paste.
Stir well and add water if the mixture is too dry. Bring to a boil, lower heat to a simmer, and let the masala cook about five minutes.
Check if the sweet potatoes are done. Add the cashew paste and salt to taste and stir well. Turn off the heat.
Stir in the lemon juice and coriander.
Serve hot with rice.