Cut squash into 2-inch pieces, leaving the skin on and place into a large soup pot or dutch oven.
Peel and dice the potatoes into 1-inch cubes
Cover the vegetable with stock and bring to a boil. Reduce heat, cover, and simmer for about 20 minutes or until the squash and potatoes are tender.
Add 1 tablespoon of the dill, butter, salt, and pepper. Remove from heat and let it rest for 10 minutes.
Puree the soup in small batches in a food processor or blender. Return to the cooking pot, stirring in the remaining 2 tablespoons of dill, and heat through.
Sprinkle sliced scallions on top just before serving. Add a few croutons if you like!