Ingredients
Equipment
Method
Preheat and start the sauce
- Preheat oven to 375°F, then butter a 9x13-inch baking dish.
- Melt butter in a saucepan, cook garlic for 30 seconds, and whisk in flour for 1 minute.
- Gradually whisk in the milk and cream, then simmer until slightly thickened.
- Season the sauce with salt, black pepper, and fresh thyme leaves.
Layer and bake
- Layer potatoes and onion in the dish in three layers, pouring sauce over each layer.
- Cover with foil and bake for 1 hour at 375°F.
- Uncover, sprinkle with Parmesan, and bake 25-30 minutes at 375°F until golden and fork-tender.
Rest and serve
- Rest scalloped potatoes for 15 minutes before serving to help the layers set.
Notes
For the best texture, slice potatoes to a consistent 1/8 inch thickness so they bake evenly and turn fork-tender. Refrigerate leftovers in a covered container up to 3 days; reheat in a 325°F oven until warmed through. Freezing is not recommended because the creamy sauce can become grainy after thawing. Vegetarian swap: replace butter with plant-based butter and use vegetarian Parmesan (no rennet if applicable) for a dairy-forward vegetarian version.
