Preheat a large pot over medium-high heat.
Add butter and completely melt.
Add onions and garlic and cook until soft.
Add sesame and pumpkin seeds, almonds, cloves, star anise, allspice, peppers, and cinnamon stick, and cook 1 minute more.
Add butternut squash and pear. Cook until spices are fragrant and squash is slightly browned (about 10 minutes).
Add milk, salt, and white pepper, and bring to a boil.
Reduce heat and simmer until vegetables are soft, about 20 minutes, stirring constantly.
Transfer soup to a blender and purée into a smooth consistency, about 2 minutes. Work in batches, if necessary.
Serve hot and garnish with toasted pumpkin seeds, if desired.