Heat olive oil in a large Dutch oven or pot over medium-high heat until shimmering.
Add the onions, tomatoes and garlic. Cook until onions soften and become translucent, about 5 minutes.
Add oregano, salt, thyme, cumin, red pepper flakes and black pepper. Stir and cook for another 4 minutes until very fragrant.
Add black beans, broth and stir to mix. Cover and cook for 15 minutes. The soup will be boiling by the end.
Uncover and carefully blend the soup with a hand held immersion blender until it reaches your desired consistency. If you don't have an immersion blender, carefully transfer some of the soup into a large blender using a ladle and blend until smooth. Then return the pureed soup to the pot and stir.
Cook uncovered for another 5-10 minutes, until the soup reaches your preferred thickness. If you cook it too long and want to thin it out, add in more broth.
Season with more salt to taste and serve with optional toppings like diced avocados, queso fresco, chopped cilantro and sour cream..
To make using dried beans, you'll need 1 1/2 cups dried beans (or 3/4 lb), about 4 1/2 cups cooked. Cook them according to package instructions or visit this post for further instructions.Adjust the amount of red pepper flakes to your liking. If you are sensitive to spicy foods, you can leave out the red pepper flakes completely. If you want this to be a really spicy black bean soup, I recommend doubling the amount!If you only add one additional topping, I recommend squeezing in some fresh lime juice. It adds a punch of brightness and acidity that compliments the creamy and savory black beans so well!Store the soup in the fridge for up to 5 days in an airtight container.To freeze, cool the soup completely in the fridge. Once chilled, scoop into freezer-safe zip-top bags or containers and freeze. When ready to eat, let frozen container thaw completely in the fridge or defrost in the microwave. Reheat on the stove or in the microwave until completely warm.