In a large sauce pan or soup pot, melt the butter. Add onion and garlic, and cook 9-10 minutes until soft. Add curry, stir and cook another 2 minutes. Check for salt and pepper, if needed.Add apples, corn (reserving some kernels for garnish) and chicken stock. Bring to boil and simmer for 45 minutes. Puree the soup with an immersion blender or in small batches in an upright blender (returning the pureed portions to the pot).Serve hot and garnish with reserved corn kernels, red pepper and basil. If using, also garnish with crab meat and a drizzle of cream or yogurt.