Rinse the beef or goat meat under cold water and pat dry with paper towels.
In a large pot, heat the vegetable oil over medium-high heat.
Add the meat cubes and sear on all sides until browned. Remove the meat and set aside.
In the same pot, add the chopped onion and minced garlic. Sauté until the onion is translucent, about 5 minutes.
Add the chopped tomatoes and green bell pepper. Cook for another 5 minutes until the tomatoes begin to break down.
Stir in the tomato paste, paprika, ground cumin, salt, and black pepper. Cook for another 2 minutes to allow the flavors to blend.
Return the seared meat to the pot.
Pour in the water or beef broth and add the bay leaf. Stir to combine.
Bring the mixture to a boil, then reduce the heat to low. Cover and let it simmer for about 1.5 to 2 hours, or until the meat is tender.
Stir in the vinegar and let the sauce simmer for another 5 minutes.
Garnish with fresh chopped parsley or cilantro before serving. Serve hot with rice, potatoes, or your favorite side dish.
Enjoy your meal!