Ingredients
Equipment
Method
Prep and preheat
- Preheat the oven to 375F and butter a 9x13-inch baking dish.
Make the creamy sauce
- Melt butter, then cook minced garlic for 30 seconds.
- Whisk in all-purpose flour and cook for 1 minute.
- Gradually whisk in whole milk and heavy cream, then simmer until slightly thickened.
- Season the sauce with salt, black pepper, and fresh thyme leaves.
Layer and bake
- Layer the sliced russet potatoes and thinly sliced onion in the baking dish in three layers.
- Pour sauce over each layer so the potatoes are evenly coated.
- Cover with foil and bake for 1 hour at 375F.
- Uncover, sprinkle grated Parmesan on top, and bake 25-30 minutes at 375F until golden and fork-tender.
Rest and serve
- Rest the scalloped potatoes for 15 minutes before serving for cleaner, easier portions.
Notes
For the best texture, keep potato slices around 1/8 inch so they cook evenly; if the top browns too fast during the final bake, loosely tent with foil. Refrigerate leftovers in an airtight container up to 4 days. Freezing is not recommended because the potatoes can soften and the cream may separate after thawing. For a lighter option, use half-and-half in place of heavy cream and reduce Parmesan by 2 tablespoons.
