Place cowpeas, chicken stock, butter, and salt into a large saucepan. Bring to a boil. Once it reaches a boil, lower to simmer.
Meanwhile, sauté diced red bell pepper in olive oil until al dente. Dice onion. When peas are just about (about 30 minutes on simmer), pour into bowl and sprinkle bell peppers and raw onion on top. Serve.