We've all been there, we've spent AGES cooking only to have a soup too watery in texture. Although this recipe will naturally thicken on it's own, luckily there are a few simple ways on how to make black bean soup thicker. - Blend half of the soup with a food processor or blender adding it back to the soup and cook for an additional 5 - 10 minutes; or - In a separate bowl, stir through a ladle of soup with a 2 teaspoons of corn flour until it's well combined. Stir the flour through the soup on a medium heat where the soup should thicken in 5 - 10 minutes. It's important to mix the flavour in a separate bowl because if the flour is added directly to the soup, it will create clumps of flour which are unpleasant to eat.