Step 1

Roast the squash: Preheat oven to 400°F. Use a heavy chef's knife or cleaver (it helps if you have a rubber mallet as well) to cut the kabocha squash half into a few large pieces. (Kabocha squash is thick and meaty and can be a challenge to cut. So take care! Make sure the squash is stable on your cutting board before you start to cut it.)Scoop out the seeds (you can toast them like pumpkin seeds!) and stringy insides. Place the squash pieces on a foil or silpat lined roasting pan. Rub olive oil over all sides, and sprinkle with salt. Put the squash pieces skin side up on the pan. Roast for 45 minutes to an hour, until completely cooked through, soft, and caramelized at the edges. Remove from oven and let sit.

Step 2

Sauté onions, celery, garlic, ginger, cumin, coriander: Heat olive oil on medium high heat in a large (4 to 6 quart) thick-bottomed pan. Add the onions and celery. Lower the heat to medium and cook until softened, 8 to 10 minutes.Add the garlic, ginger, cumin, and coriander and cook 2 minutes more.

Step 3

Add squash, stock, salt, pepper, then simmer: Once squash is cool enough to handle, remove and discard the skin. Place the roasted kabocha squash flesh into the pot with the onions and celery mixture. Add the stock, salt and pepper. Increase heat to high to bring the soup to a simmer, then lower the heat to low, partially cover and cook 8 to 10 minutes.

Step 4

Purée the soup: Remove from heat. Use an immersion blender (or work in batches with a standing blender, only filling the blender bowl 1/3 of the way each time) to purée the soup.Add more salt to taste. Sprinkle with lime juice and chopped cilantro to serve.