Rinse the white fish fillets under cold water, then pat them dry. Cut into bite-sized pieces, season with salt and pepper, and set aside.

In a large pot, heat 2 tablespoons of oil over medium heat. Add chopped onions and sauté for about 5 minutes.

Stir in minced garlic and grated ginger into the pot, cooking for an additional 1-2 minutes.

Add diced tomatoes and finely chopped bell pepper to the pot. Cook for 5-7 minutes.

Pour in coconut milk and broth. Stir and bring to a gentle simmer for about 3-5 minutes.

Stir in fish sauce, lime juice, and curry powder. Adjust seasoning with salt and pepper.

Gently add fish pieces into the stew. Cook for about 10 minutes until fish is cooked through.

Stir in spinach or kale and cook for an additional 2-3 minutes until wilted.

Ladle into bowls, garnishing with fresh cilantro and serve with lime wedges.