1. **Prepare the Soup Base:**
1. Heat the olive oil in a large pot over medium heat.
2. Add the chopped onion and sauté until it becomes translucent (about 5 minutes).
3. Add the minced garlic and cook for another minute.

2. **Cook the Ground Beef:**
1. Add the ground beef to the pot and cook until browned, breaking it up with a spoon as it cooks. Drain any excess fat if necessary.

3. **Add Vegetables and Spices:**
1. Stir in the diced carrots, celery, and red bell pepper. Cook for about 5 minutes until the vegetables start to soften.
2. Add the tomato paste, smoked paprika, ground cumin, chili powder, and dried oregano. Stir well to combine.

4. **Simmer the Soup:**
1. Pour in the beef broth and add the diced tomatoes (with their juice). Bring the soup to a boil.
2. Reduce the heat to low and let it simmer for about 30 minutes, or until the vegetables are tender and the flavors have melded together. Stir occasionally.

5. **Season and Serve:**
1. Season the soup with salt and pepper to taste.
2. Stir in the chopped parsley just before serving.

6. **Garnish:**
1. Ladle the soup into bowls and garnish with a dollop of sour cream and sliced green onions.

Enjoy your hearty ground beef and vegetable soup!

Enjoy!