Heat the vegetable oil in a medium pot over medium-high heat. Add the onion and red pepper. Cook until softened, stirring occasionally, about 2 minutes. Add the garlic, ginger and curry paste and cook for 30 seconds. Add the chicken broth, coconut milk and brown sugar. Cover and bring to a boil.
TIP: For a gluten free, paleo, low-carb version of this soup, omit the brown sugar and use shredded zucchini “noodles” instead of rice noodles.