Start by dicing the pumpkin, and slicing the onion. In a saucepan with medium heat, cook the onion and pumpkin in a little butter, then add the green curry paste.
Add the vegetable stock to the saucepan and boil until pumpkin is tender (about 10mins) with a stick blender pulse the curry sauce base so the texture is smooth and broken down. Add the coconut milk and herbs and season with lime zest and juice, salt and pepper.
Now you have the base to the curry you can add pretty much whatever you like. Chicken, beef, turkey, potatoes, or any left over meats.