For roasting squash, preheat oven to 375 degrees. Line a rimmed baking sheet with foil. Slice squash in half, along the vertical line, and scoop out seeds. Drizzle flesh sides with olive oil and kosher salt and black pepper. Place the halves, flesh side down, on the baking sheet. Roast for 50-60 minutes until the flesh of the squash is fork tender. Remove from oven and set aside cool. Scoop out flesh and set aside. NOTE: you can roast the squash a day or two in advance and store in the fridge until the day of soup prep.

In a cocotte or Dutch oven, heat a tablespoon of olive oil over medium heat. Add onions along with a pinch of salt and pepper. Cook onions over low heat to allow them to caramelize, stirring occasionally, for 7 to 10 minutes. Add garlic and cook for 1 minute until fragrant. Add in the roasted squash and stir to combine. Add stock, turmeric, cayenne pepper, and bring to a simmer. Simmer 10-15 minutes. Taste and adjust seasoning as desired.

While soup simmers, prep croutons by drizzling the bread cubes with olive oil and season with a pinch of salt and pepper. Toast the cubes in a 350 degree oven for 5-10 minutes until golden and crispy. Remove and cool slightly. If using pancetta, sauté in a small skillet until crispy, about 5 minutes. Drain pancetta on a plate lined with a paper towel. Set aside to top soup with later.

Using an immersion blender, blend the soup until smooth and creamy. Finish the soup with butter and milk. Alternatively, you can blend the soup in a blender and then add the soup back into the pot to finish with butter and milk.

Ladle soup into bowls. Top with croutons, pancetta, chopped chives, and a drizzle of olive oil, if desired.