1. Prepare the Aromatics

1. Heat the Oil: In a large pot or Dutch oven, heat the olive oil over medium heat.
2. Sauté Onion and Garlic: Add the chopped onion and cook for 2-3 minutes until softened and translucent. Stir in the minced garlic and grated ginger, cooking for another minute until fragrant.

2. Build the Soup Base

1. Add Red Curry Paste: Stir in the red curry paste and cook for 1-2 minutes to release its aroma and deepen the flavor.
2. Add Broth and Coconut Milk: Pour in the chicken broth and coconut milk, whisking to combine. Add the lemongrass if using.
3. Season the Broth: Stir in the fish sauce, brown sugar, and soy sauce. Bring the mixture to a gentle simmer.

3. Add Chicken and Vegetables

1. Add Chicken and Carrots: Stir in the cooked chicken and julienned carrots. Let simmer for 5 minutes.
2. Add Bell Pepper and Mushrooms: Add the red bell pepper and mushrooms, cooking for another 3-4 minutes until the vegetables are tender but still vibrant.
3. Add Greens: Stir in the baby spinach or kale and cook until wilted, about 1-2 minutes.

4. Final Touches and Serving

1. Add Lime Juice: Stir in fresh lime juice to brighten the flavors. Taste and adjust seasoning with more fish sauce, soy sauce, or lime juice as needed.
2. Serve: Divide the soup into bowls and add cooked rice or rice noodles if desired. Top with fresh cilantro, green onions, red chili slices, and lime wedges for garnish.