How to Make It
Preheat oven to 450°. Line a baking sheet with aluminum foil. Wrap aluminum foil around the bottom detachable portion of a 10.5-inch springform pan.
Place 2 butternut squash halves cut-side down in an 8x8” microwave-safe baking dish; fill with ½ inch of water. Cover with plastic wrap and microwave on HIGH until just tender enough to pierce with a skewer, about 5 minutes. Remove from microwave and let sit, covered, 5 minutes more. Repeat with remaining butternut squash.
Cut off top of acorn squash and remove seeds, creating a hollow center. Place in microwave-safe baking dish with 1/2" inch of water, cover with plastic wrap, and microwave on HIGH 5 minutes, as above. Remove from dish; set aside.
Cut butternut squash halves in half lengthwise, to make 8 slices. Cut each slice in half lengthwise again, leaving you with 16 slices.
Place foil-wrapped springform base in the center of prepared baking sheet. Place acorn squash, hollow side up, in center of springform base. Using a 4-inch bamboo paddle skewer, pierce the flesh side of a butternut squash slice, about 2 inches from the top, and push skewer through the skin side in a diagonal downward direction, so the skewer is sticking out of the skin side. Secure butternut slice to acorn squash by standing the slice vertically against the outside of the acorn squash and inserting the skewer into the acorn squash, about ½ inch from the top. Repeat with remaining skewers and butternut slices to completely surround acorn squash, resembling a crown roast. You should use 12 slices of squash.
Combine maple syrup, brown sugar, and canola oil in a small bowl. Whisk to combine. Brush ¾ of the mixture over butternut squash. Reserve remaining mixture.
Bake in preheated oven for 45 minutes, or until edges are browned.
Remove from oven, reduce oven temperature to 400°. Mix salt with remaining maple syrup mixture, brush remaining mixture over butternut squash.
Spoon stuffing into center of acorn squash to fill and come up through the center of the roast. Bake in oven until stuffing is completely heated through and browned on top, about 20 minutes.
Remove from oven, let cool until warm enough to handle, about 20 minutes. Remove springform pan, with roast on top, from the baking sheet and place on serving platter. Garnish stuffing with thyme leaves. Place cranberries on ends of skewers, if desired. Garnish with parsley leaves, rosemary springs, thyme springs, and sage leaves, if desired.