Add oil and curry paste to a large saucepan set over medium-high heat, Break up the curry paste and toast until aromatic. Add ginger, garlic, shallot, and red pepper and cook until soft and translucent, ~3 mins.
Stir in pumpkin puree and cook until thick and reduced, ~5 mins. Add coconut milk, broth, brown sugar, fish sauce, sweet potato and mushrooms.
Bring to a boil then reduce heat to a simmer; cook until flavors meld, ~10 mins.
Use immersion blender to blend ingredients into a thick consistency. Adjust with additional chicken broth as needed. Taste and season with salt as needed.
Add green beans and continue to simmer. Add cilantro and Thai basil.
Serve with garnishes.