- Quarter the pumpkin and remove the seeds. Peel and slice into 1-inch cubes. 
- Add the oil to a large high-sided skillet or Dutch oven over medium-low heat.  
- Sauté the onions until translucent, about 6 minutes. 
- Add the pumpkin and continue sautéing for 8-10 minutes, stirring often. Add the peppers, lime leaves, and ginger. 
- Once the peppers begin to soften, add the garlic, curry paste, and coconut sugar. Stir for a few minutes, until very fragrant, then add the fish sauce. 
- Simmer for 5 minutes, then slowly stir in the coconut milk and cashews. 
- Allow the curry to simmer gently, stirring often and reducing the heat as needed, until the pumpkin is fork-tender. Just before serving, add the juice of 2 limes. 
- Serve the curry over rice and top with cilantro and scallions.