1In 4-quart nonstick Dutch oven, heat oil over medium heat. Add onion and mushrooms; cook 3 minutes, stirring frequently. Add bell pepper and garlic; cook 2 to 3 minutes longer, stirring frequently, until vegetables are tender. Remove from heat; stir in curry paste until melted.
2Stir in broth, chicken, brown sugar and salt. Return to heat. Heat to boiling. Reduce heat; simmer uncovered 5 minutes, stirring frequently.
3In small bowl, stir cornstarch and water until smooth. Add cornstarch mixture and coconut milk to soup mixture; heat to boiling. Cook over medium heat about 2 minutes, stirring frequently, until slightly thickened.
4Stir in spinach and cilantro. Cook about 1 minute or just until mixture is hot and spinach is wilted. Serve soup with lime wedges.