In a large skillet on high heat, add the oil and onion, and cook until slightly soft. Add the ginger and garlic, and cook for another minute until soft.
Add the mushrooms, kale, carrots and peppers. Cook for about five minutes until tender, stirring as you go.
Then add the curry paste, and cook for another minute.
Add the coconut milk and sugar, and stir together.
Bring the mixture to a boil, then turn the heat to medium and simmer gently for about 10 minutes, stirring.
Remove from heat and season with tamari, fish sauce (if using), and lime juice.
Adjust the seasoning to taste, remembering to balance salty, sweet and spicy with acidity.
