In a large bowl, combine the gluten free flour, cornmeal, baking powder, salt and sugar.
In a small bowl, combine the melted butter, eggs and milk.
Add the wet ingredients to the dry ingredients and stir to combine.
Spread the cornbread mixture into a greased 9 x 13 inch baking dish.
Place in the oven for 30-35 minutes.
In the meantime, prepare the squash.
Place the butternut squash on a foil-lined baking sheet and drizzle the olive oil over the squash. Sprinkle 1 tsp salt and 1 tsp pepper on top.
Place in the oven with the cornbread and roast for 15-20 minutes.
Once the cornbread and squash are cooked, remove from the oven and set the squash aside.
Allow the cornbread to cool then slice into cubes and set aside.
Add the remaining 2 tbsp olive oil & 2 tbsp butter to a large pot over medium heat, once the butter is melted, add the onion, celery and cranberries, cook 7-9 minutes.
Add the remaining 1 tsp salt and pepper, and sage.
Add the roasted squash and cornbread to the pot, gently stir to combine.
Cover with the vegetable broth and bring to a boil.
Cover the pot with a tight fitting lid and place in the Wonderbag.
Close the Wonderbag tightly and let the stuffing slow cook in the bag for 4-6 hours.