Choose any nutty-flavor cheese to fill this apple-potato gratin with gooey goodness. Save yourself a little labor by shredding apples with peels intact.
Prepare as directed, except cook the potatoes and apples in separate pans of lightly salted boiling water for 5 minutes. Drain; pat dry with paper towels. Continue as directed through Step 1, except do not preheat oven. Chill for up to 24 hours. To serve, let stand at room temperature for 30 minutes. Preheat oven to 350 degrees F. Continue as directed in Step 2.