In a large skillet, saute the bell pepper, onion & garlic in oil over medium heat until the peppers are tender-crisp, about 3 minutes. Add the potato & yam & cook for 5 mninutes, stirring constantly. Add the tomatoes. Cover, reduce the heat to low & simmer for 5 minutes. Gradually add the broth & continue to cook until the potatoes have softened & the skins have split on the tomatoes, about 15 minutes. Add the peas & season with cayenne to taste. Simmer until heated through & serve hot.