Place your prepared squash in a 9×13 inch roasting tin and toss with ¼ cup of olive oil, salt and pepper. Arrange the squash in a single layer and add the fresh thyme sprigs. Roast until the squash is tender when pierced with a knife, approximately 30 minutes. Remove from the oven and set aside.
In a large pot, warm the remaining 2 tablespoons of olive oil over medium heat. Add the onion, garlic, and pancetta and sauté, stirring occasionally, until the onion is softened, and the pancetta is lightly browned, about 5 -7 minutes. Add the cooked squash and white wine and bring to a simmer. Allow the wine to reduce until there is hardly any liquid left in the pot, about 5 minutes. Add the bay leaf, peppercorns and vegetable stock. Cover and cook on low heat for about 20 – 25 minutes.
Remove from the heat and discard the bay leaf, pancetta, sprigs of thyme and peppercorns (they usually are not too hard to find since they are black in a mostly orange pot!) Using an immersion or stand blender, puree the contents until smooth. If you find the soup too thick, add some water a little at a time. Season to taste and serve piping hot with a dollop of crème fraiche, if desired, and some fresh bread.