Step 1Melt the butter in a large saucepan over medium heat. Add the onion and cook, stirring often, until the onion has softened a bit, about 3 to 4 minutes. Add the bell pepper and corn and continue to cook until the vegetables are tender, about 5 minutes, stirring occasionally. Add the broth, bring to a boil, then reduce the heat to medium-low and simmer for 10 minutes.
Step 2Carefully ladle about half of the soup into a blender, filling it no more than halfway, and puree until smooth, about 2 minutes. You may need to do this in batches. Return the puree to the saucepan and season with salt and a generous amount of pepper. Add the crab and cook just until heated through, about 2 minutes. Garnish with the chives.