Preheat oven to 400 degrees.
Combine butternut squash, red and yellow onions and toss with syrup, brown sugar and olive oil, roast for 20 minutes.
Melt 6 Tbsp of butter in a pan, and add a handful of torn sage leaves into the butter for 1 minute.
In a large bowl, combine brioche with roasted butternut squash mixture and pour butter into the bowl.
Toss to combine and slowly mix in 1.5-2 Cups of chicken stock, until the stuffing is fluffy and moist.
Spoon stuffing into a baking dish and finish in the oven at 400 degrees for 15 minutes, garnish with fresh sage leaves.