Sauté the onion in a deep pan or pot in the oil for about 5 minutes until the onion goes soft and translucent. Add the garlic and cook for another minute.
Add the garam masala, cumin, coriander, cayenne pepper, black pepper and turmeric. Mix all the spices with the onions and garlic and cook for a minute or two.
Add the chopped tomatoes, tomato puree, agave syrup, drained black beans, chopped pepper and juice of one lime.
Add the peanut butter. Stir everything in and bring to the boil. Be sure that the peanut butter is mixed evenly. Turn down to a gentle simmer for around 10 minutes stirring regularly.
While the curry is cooking, prepare the rice according to the packet instructions.
Once everything is ready, serve the curry along with the rice.