in a 350 degree over, roas the butternut squash until tender (approximately 1 hour). Let cool slightly, then remove flesh from skin, place in large bowl and mash until smooth consistency.
Add salt and pepper to taste. If desired, add Cinnamon and nutmeg. Chill before filling dough.
To prepare dough, put eh flour in a large mixing bowl and make a well in the center. Place eggs, sour cream, butter and salt in the well, then blend the ingredients together with your hands, gradually adding water and working the mixture into a smooth, pliable dough. Divide the dough into quarters and keep the unused portions covered witha damp towel while working.
On a lightly floured surface, roll out one piece of the dough 1/16" thick. Cut into 3.5-4" rounds. Place a tablespoon of the filling in the cente rof each round, fold in half and then crimp edges with fingertips or a fork. Place the finished pierogies in a single layer on a floured baking sheet.
Bring a large pot of salted water to boil. Cook the pierogies in batches of 8-10. Drop in boiling water ans stir gently to prevent sticking. Cook over med high heat until they float (3-4 min). Remove with slotted spoon and drain.
For the sauce, melt butter in a medium saute pan over med-high heat. Add maple syrum and heavy cream and cook for 1 minute. Add the sage and season with salt and pepper to taste. Ad the boiled pierogies to the pan and saute, basting with the sauce for several minutes.