Heat the vegetable oil in a large pot or Dutch oven over medium heat.
Add the meat pieces and brown on all sides. Remove the meat from the pot and set aside.
In the same pot, add the chopped onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic and ginger, and cook for another 2 minutes.
Add the chopped tomatoes, red bell pepper, and green bell pepper to the pot.
Stir in the ground paprika, ground cumin, ground coriander, ground thyme, ground black pepper, and salt. Cook for about 5-7 minutes, until the tomatoes are softened and the spices are fragrant.
Stir in the peanut butter, mixing well with the vegetables and spices.
Return the browned meat to the pot.
Pour in the water or chicken broth, and stir to combine.
Add the sweet potatoes, carrots, and green beans if using. Bring to a boil, then reduce the heat to low.
Cover the pot and let the Maafe simmer for 45-60 minutes, or until the meat and vegetables are tender and cooked through. Stir occasionally, and add more broth or water if needed.
Garnish with fresh cilantro or parsley before serving.
Enjoy your meal!