Heat a large pot to medium and add oil. Add in onion and sauté for 5 minutes, until softened. Add garlic and cook for 1 minute.
Stir in carrots, celery, roasted red peppers, tomato paste, oregano, paprika, cumin, 1 teaspoon salt, and red pepper flakes. Cook, stirring often, for 5-6 minutes, until vegetables start to soften.
Whisk flour into 1 cup of the broth.
Add to the pot with the remaining 2 cups of broth and the butter beans. Bring to a boil, then reduce heat to medium low, cover, and simmer for 25 minutes.
Remove lid and stir in spinach, parsley, and red wine vinegar. Taste and add an additional ¼ teaspoon of salt if desired. Simmer uncovered for 5 additional minutes and serve warm.