Preheat oven to 400°F. Line a baking sheet with parchment paper.

Slice off stem end of pumpkin, then halve pumpkin. Use a spoon to scoop out seeds and fibers; discard seeds or save for another use. Place pumpkin halves cut-side down on baking sheet. Roast until the pumpkin’s flesh is very soft and pierces easily with a paring knife, 30 to 40 minutes. Transfer to cutting board until the pumpkin flesh is cool enough to handle. Scoop flesh away from skin with a spoon; discard skin and set flesh aside.

Heat butter in large pot over medium heat. Add onion, apple and garlic and cook, stirring occasionally, until soft, about 5 minutes. Stir in broth, roasted pumpkin, pumpkin spice and salt. Bring to a boil, adjust heat and simmer until the apple is very soft, about 20 minutes. Puree soup with an immersion blender or transfer in small batches to a blender, puree and return to the pot. Stir in ¼ cup of the crème fraîche.

Reheat soup if necessary. Ladle into bowls and swirl about ½ tablespoon of crème fraîche into each. Top each bowl with dill, tarragon and sesame seeds. Sprinkle with pink peppercorns and flaky salt and serve.