Preheat oven to 350 degrees F (175 degrees C). Grease a 9x11-inch casserole dish.
Place squash on a flat work surface. Trim off the hard outer rind with a knife. Cut squash into 1/2-inch slices; arrange slices over the bottom of the prepared dish. Arrange apples on top.
Combine brown sugar, butter, flour, salt, and mace together in a bowl. Pour mixture over the apples. Sprinkle cranberries on top.
Bake in the preheated oven until top is golden brown and apples are tender, 50 minutes to 1 hour.
