Preheat your oven to 400 degrees fahrenheit (200 degrees celsius).
Slice the butternut squash in half with a very sharp knife. You can also cut the ends off and microwave for 2 minutes, to make it easier to slice in half lengthwise.
Scoop the seeds out of the butternut squash with a spoon.
Lightly oil the butternut squash and season with salt and pepper.
Lay the butternut squash, cut side down on a baking sheet and bake for 40-45 minutes.
While the butternut squash is cooking, add the sausage to a saute pan on medium heat. Use a spatula to break up the sausage and cook until it's just browned.
Add the onions, garlic and baby spinach to the pan and stir for 2-3 minutes, or until the spinach is wilted.
Add the apple, sage and rosemary and cook for another 2-3 minutes, or until the apple has softened slightly.
Turn off the heat and stir in the cranberries and pecans.
When the butternut squash halves are cooked through, remove them from the oven, flip them over and remove some of the flesh (but leave plenty to enjoy!) to make room for the filling. Save this removed flesh and turn it into mashed butternut squash to enjoy later!
Fill the butternut squash with the apple sausage filling.
Turn the top broiler on the oven and bake the filled butternut squash for 5 minutes, or until they're golden on top. Serve immediately.