In a saucepan, heat olive oil over medium heat and fry the onion, garlic and ginger until the onion is translucent, about 7 minutes.
Add the tomato paste (or ketchup), curry powder, and red pepper flakes and cook for another minute.
Add the vegetable broth, diced tomatoes and cow-peas. Cover and bring to a boil, then simmer on low heat for 2 hours minutes, until the cow-peas are very tender. Season with salt and pepper.