Wash the exterior of the delicata squash and apples, then cut them in half from top to bottom; don't remove the skin. You can scoop out the center of the squash and apples to remove the seeds. Place a couple of chopsticks on a cutting board on either side of the halved squash/apple; this helps keep the knife from slicing all the way through so that the cuts create an accordion effect. Place the squash and apples on a sheet pan, brush the tops with olive oil or melted butter, and sprinkle with a little salt and/or spices. If you want to, you can also tuck fresh sage in between the cuts.
Roast until tender, 15 to 45 minutes, depending on the fruit or vegetable; delicata squash and apples may take 15 to 20 minutes.
Variations: Brush the apples with maple syrup or sprinkle with brown sugar, tuck fresh thyme leaves between the cuts, and sprinkle with vanilla sea salt after roasting.