1place 1 1/2 cup of corn and 1 1/2 cup of broth in a food proccesor fitted with a metal blade or blender. process until smooth. set aside.
2Heat the oil in a large pot or dutch oven over medium-high heat. Add the bell peppers and Chile pepper and cook, stirring occasionally for 3 minutes add scallions and cook for 3 minutes or until the vegetables are tender.
3Add the fish sauce, reserved corn-broth mixture, remaining corn kernel, and remaining 1 1/2 cups of broth. Bring to a simmer and reduce heat. Cover and cook for 10 minutes or until thickened.
4stir in crab, cilantro, and red pepper. serve immediately