In a large pot over medium heat, cook onions in olive oil and sesame oil until translucent (about 5 minutes).
Add in curry paste or spices and stir to coat. Deglaze with a good splash of broth, and then stir in the rest of the broth. Raise heat and bring to a boil.
Add sweet potatoes and bring to a boil. Let cook for about 5 minutes, then add in butternut squash. Bring to boil again, then lower to simmer for about 30 minutes.
Use an immersion stick blender or a high speed blender to puree the soup. Add kosher salt to taste, and serve!