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.