Preheat oven to 350. Wash outside of squash, pierce with knife in 3-4 places, place on baking sheet and roast whole for about 1-1.5 hours, or until knife easily slides in. After squash has cooled enough to handle, cut down middle, carefully scoop out seeds, then scoop out all the pulp. At this point, the squash pulp can be tightly covered in a container and placed in the refrigerator for a few hours or days, until you are ready to use it.
Put olive oil in large heavy bottomed pot over medium high heat. Saute onion and carrots until slightly brown.
Stir in cooked butternut squash pulp, broth and Tabasco chipotle sauce; combine well. Heat to a boil, then reduce heat and simmer uncovered for 15-20 minutes.
Remove from heat and use an immersion blender to puree the soup until smooth. Season with salt and pepper to taste.
Serve garnished with sour cream or plain yogurt, roasted pumpkin seeds, chopped cilantro, and extra chipotle sauce.