Place cubed squash, diced onion, garlic, rosemary, sage and broth into a 6-7 quart slow cooker. Stir well and cook on high for 4 1/2 hours or on low for 8-9 hours.
If using fresh sage, remove leaves. Process soup with an immersion blender or stand blender. Add soup back to slow cooker and stir in fresh tortellini. Cook on high for an additional 10 mins.
Meanwhile, place bacon strips into a cold frying pan. Cook over med/high heat until golden and crispy, about 5 mins, turning halfway. Place cooked bacon on paper towels and once cooled crumble.
Temper sour cream with about 1/2 cup of liquid from soup. Stir into slow cooker and continue cooking on high for another 5-10 mins. Garnish with bacon crumbles.
Notes
Please use as many organic ingredients as possible. To lower calories use low-fat or fat free plain yogurt and omit the bacon.