Add the onion and Serrano pepper and cook for 6-7 minutes, or until the onions begin to brown.
Add garlic, spices and ground beef and mix well.
Once the beef begins to brown, add the butternut squash and mix well.
Reduce the heat to medium-low, cover with a lid for 10 minutes, or until the butternut squash is cooked through.
Remove the lid, add fresh sage and mix well.
Serve.
Notes
*I bought pre-cut organic butternut squash (at costco) and then cut it into even smaller cubes. You can do this with a regular butternut squash but it'll add to your prep time.