Ingredients (~6 servings)
- 3 Tbsp butter
- 1/4 cup all-purpose flour
- 1 1/4 tsp salt
- 1/4 tsp black pepper
- 2 1/2 cups whole milk
- 2 1/4 lbs potatoes, peeled and sliced into 1/8″ slices
- 1/2 large onion, thinly sliced
Make the Cream Sauce Base
Preheat your oven to 350F and grease a 9×9 baking dish.
In a medium saucepan, melt the butter over medium heat. Whisk in the flour, salt, and pepper until smooth – this creates your roux base.
Gradually whisk in about 1/2 cup of the milk first to prevent lumps from forming. Once that’s smooth, add the remaining milk and whisk constantly.
Bring the mixture to a boil while stirring constantly. The sauce will thicken noticeably after ~3-4 minutes of boiling. Once it coats the back of a spoon, pull it off the heat.
Layer the Potatoes and Onions
Arrange 1/3 of the potato slices in the bottom of your baking dish, overlapping slightly.
Top with 1/3 of the onion slices, then pour 1/3 of the cream sauce over everything.
Repeat this process two more times – potatoes, onions, sauce – ending with sauce on top.
The top layer of potatoes should be mostly covered with sauce; if not, the exposed edges will dry out.
Bake Until Fork Tender
Cover loosely with foil and bake for ~75 minutes.
Remove the foil and bake for another 15 minutes to brown the top slightly.
Test doneness by piercing the potatoes with a fork – it should slide through easily with no resistance. If the potatoes still feel firm, continue baking in 10-minute increments until tender.
Let rest for ~10 minutes before serving; the sauce will thicken as it cools.
Scalloped Potatoes
Ingredients
~6 servings
- 3 Tbsp butter
- 1/4 cup all-purpose flour
- 1 1/4 tsp salt
- 1/4 tsp black pepper
- 2 1/2 cups whole milk
- 2 1/4 lbs potatoes peeled and sliced into 1/8″ slices
- 1/2 large onion thinly sliced
Instructions
- Preheat oven to 350F and grease 9×9 baking dish.
- Melt butter in saucepan, whisk in flour, salt, and pepper to make roux.
- Gradually add milk, whisking to prevent lumps.
- Bring sauce to boil, stirring until thickened, about 3-4 minutes.
- Layer 1/3 potato slices in dish, overlapping.
- Top with 1/3 onion slices and 1/3 cream sauce.
- Repeat layering twice more, ending with sauce covering potatoes.
- Cover with foil and bake 75 minutes.
- Remove foil, bake 15 more minutes until top browns.
- Test potatoes with fork for tenderness.
- Let rest 10 minutes before serving.
