Preheat oven to 450 F. Bake potatoes for 60 minutes but do not wrap in aluminum foil. While potatoes are baking, steam the squash. I heat the squash in the microwave until it's tender enough to slice. Scoop out the rind into a large bowl. Once the potatoes can be easily pierced with a fork, slice them in halves. Scoop out the potatoes from the skins and place in the bowl with the squash. Combine vegan margarine and preferred seasonings and mash together. Drop the oven temperature to 350 F.
Bake manicotti shells according to package. I bake the shells for 5 minutes. Once drained, place on wax paper or aluminum foil to avoid sticking. Spoon mixture into shells and place in a casserole dish. Cover with sauce and, if desired, vegan cheese. Bake for 30-40 minutes. Enjoy!
Source of recipe: I wrote this recipe after experimenting in the kitchen.