Place the squash halves on 2 sheet pans cut-side up. Drizzle with olive oil and sprinkle generously with salt. Roast until fork-tender, about 20 minutes. Set aside until cool enough to handle.
Meanwhile, add the potatoes to a pot of heavily salted water. Bring to a boil and cook until fork-tender, about 15 minutes. Drain and set aside.
Add olive oil to coat the bottom of a heavy-bottomed stockpot over medium-high heat. When the oil starts to shimmer, add the leeks and saute until wilted, about 5 minutes. Add the garlic and red pepper flakes and cook until translucent, another 2 minutes. Add the celery and a big pinch of salt and saute until soft, about 5 minutes more. Add the potatoes and fold to combine. Add the white wine and vegetable stock and bring to a boil. Reduce to a simmer and cook until the flavors have melded and vegetables are soft, about 10 minutes.
Scoop out the flesh of the squash and add to the pot. Using an immersion blender, blend until smooth. Add the cream and blend once more until velvety. Taste and adjust the seasoning. Serve with toasted pepitas, a drizzle of pumpkin seed oil and goat cheese crumbles. Enjoy!