In a large saucepan or Dutch oven, heat the oil over medium heat.
Add the sliced onion and chopped bell pepper.
Cook for 5-7 minutes, stirring occasionally, until softened and lightly golden.
Stir in the crushed red pepper and cook for 1 minute more until fragrant.
Pour in the vegetable broth and add the chopped peanuts, stirring to combine.
Bring the mixture to a boil.
Add the new potatoes and sweet potato pieces. Return to a boil, then reduce the heat to low, cover, and simmer for about 25 minutes, or until the potatoes are fork-tender.
Stir occasionally to prevent sticking.
Stir in the rinsed fava beans and the undrained diced tomatoes. Increase the heat to medium and cook for 3-5 minutes, until the stew is heated through.
Ladle the stew into bowls. If desired, top each serving with a dollop of vegan sour cream and a sprinkle of fresh chives before serving.