Preheat the oven to 425F.
Remove the seeds from the squash, peel the garlic cloves and slice the onion into large pieces. Place all the vegetables on a piece of foil large enough to wrap around them.
Cover the vegetables with olive oil, salt and pepper and loosely wrap the foil around the top. Roast at 425F for about 30-35 minutes or until the garlic is soft and the squash is fully cooked.
While the vegetables are roasting, cook the farro per package instructions, drain and set to the side.
When the vegetables are done roasting, let them cool for 5 minutes then move them to a blender. Make sure to remove the peel from the squash.
Add the red pepper flakes and cup of water and blend until a smooth purée forms. Feel free to add more water as needed.
Pour the purée onto the farro and mix to combine. Season with more salt, pepper and red pepper flakes if desired.
To make the crispy sage, roughly chop the sage leaves and toss in a small coating of olive oil. Spread it on a baking sheet and broil on high for 3 minutes or until the sage is crispy.
Top the farro with the sage and optional parmesan, and serve!