- With the rack in the middle position, preheat the oven to 350°F (180°C).
- On a work surface, cut the squash in half near to where the bottom becomes rounded. Cut the bottom piece in half and remove the seeds. Using a mandoline or chef’s knife, cut the squash pieces, the carrots and apple into thin 1/8-inch (3 mm) slices. Place in a large bowl with the garlic, melted butter and salt. Mix well. Spread out in an even layer in an 8-inch (20 cm) square baking dish, pressing down lightly.
- Bake for 1 hour or until the vegetables are tender when pierced with a knife.
- Meanwhile, in a small bowl, whisk the apple jelly with a fork. Add the cranberries and rosemary. As soon as the vegetables are out of the oven, top with half of the apple jelly mixture. Let sit for 10 minutes and serve with the remaining jelly on the side.