Butternut, Brown Butter & Sage Soup

Preheat large (~5qt) enameled cast iron Dutch oven or similar heavy pot over medium heat. Melt 3Tbs butter. Once the butter is hot and frothy, add sage leaves in 2-3 batches, cooking each leaf for 20-30 seconds or until crisp, remove with chopsticks, large tweezers, or tongs. Drain cooked sage on a paper towel-lined plate and save for a garnish (crumble once cool). The butter should be fragrant and brown at this point. Add onions, white pepper, and a pinch of salt. Cook briefly until onions are translucent. Add squash and another pinch of salt. Stir, pour in 1 cup of broth and quickly cover with the lid. Allow to steam 5-10 minutes then add the remaining stock. Replace the lid and reduce the heat to medium-low. Let simmer 30-45 minutes until squash is soft.
Meanwhile, clean the reserved squash seeds of any major pulp pieces and place them in a broiler-proof pan. Place a small pat of butter on top of seeds and sprinkle on a little salt and white pepper. Broil until seeds are brown, fragrant, and start popping (first stir in the butter once it melts after the initial heat of broiling). Allow seeds to cool and save for garnishing the soup.
When the squash is soft, finish the soup by removing the pot from the heat and pureeing until smooth with an immersion blender. Stir in vinegar. Taste and adjust for seasoning. Ladle into bowls and garnish the top with toasted squash seeds, crumbled fried sage leaves, and a sprinkling of Maldon or other finishing salt. Enjoy!