Our test kitchen director used a food processor with a slicing attachment to cut the spuds into rounds in seconds.
- ½ stick butter
- 1 Tbs. flour
- 2 cups milk
- 1 Tbs. minced fresh thyme
- 4 baking potatoes, peeled and sliced into ¼”-thick rounds
- 1 cup grated Parmesan cheese
- ½ cup grated Gruyère cheese
- 1 bunch fresh chives, sliced
- Heat oven to 400°F. In pan over medium heat, melt butter. Whisk in flour; add milk. Let simmer 5 min. or until thickened, whisking. Add thyme.
- Spread ¼ potato slices in bottom of 9″ x 13″ greased casserole dish. Ladle ½ cup milk mixture over top; sprinkle with ¼ cup Parmesan and 2 Tbs. Gruyère. Repeat layering 3 times. Cover with foil; bake 1 hr., uncovering during last 10 min. Top with chives.