Preheat oven to 375
Cut ends off of squash, slice in half length wise and scoop out seeds.
Place squash cut side up on baking sheet.
Brush squash with olive oil.
Toss garlic cloves with olive oil and place on the baking sheet.
Bake until squash is fork tender, about 45 minutes.
Prep the seeds:
Clean off pulp and boil seeds for 10 minutes.
drain the seeds and blot with a towel. Place on a baking sheet and season with salt.
Place in a 375 degree oven for 20-30 minutes, tossing every 10 minutes or so, until seeds are golden.
Once the squash is cool enough to handle, scoop out the flesh and place in a blender or food processor.
Squeeze the roasted garlic out of its skin, and add to the blender as well.
Add sage leaves, half and half, salt and pepper.
Puree until smooth.
Pour sauce into a medium sauce pan to warm.
Add nutmeg and stir.
To cook the tortellini:
Bring water to a boil in a large sauce pan.
Add tortellini and follow package instructions.
Strain Tortellini and return back to the pan.
Add the butternut squash sauce to the pasta and stir to combine.
Add some water if it is too thick.
Serve pasta with thick shreds of fresh parmesan cheese and toasted squash seeds.