Heat the oil in a large nonstick saucepan over medium-high heat. Add the ginger, red curry paste, scallions and garlic. Cook, stirring frequently, until fragrant, 2 to 3 minutes. Add the potatoes, broth, brown sugar and nutmeg and bring to a boil. Reduce the heat and simmer, partially covered, stirring occasionally, until the potatoes are fork-tender, about 20 minutes.
Transfer the soup, in batches, to a food processor or blender and blend until smooth. Return the soup to the saucepan. Stir in the coconut milk and lime zest and juice and heat through. Serve at once.
Per Serving: 220 Cal; 7 g Protein; 6 g Tot Fat; 3 g Sat Fat; 1 g Mono Fat; 38 g Carb; 4 g Fiber; 15 g Sugar; 68 mg Calcium; 2 mg Iron; 121 mg Sodium; 0 mg Cholesterol