Ingredients
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3 lbs russet potatoes, thinly sliced (⅛ inch thick)
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3 tbsp butter
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1 small onion, finely chopped
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3 cloves garlic, minced
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3 tbsp all-purpose flour
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2 cups whole milk
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1 cup heavy cream
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1 tsp salt
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½ tsp black pepper
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½ tsp paprika
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2 cups shredded sharp cheddar cheese
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½ cup grated parmesan cheese
Instructions
Step 1 – Preheat oven
Preheat oven to 375°F. Grease a 9×13 baking dish.
Step 2 – Slice potatoes
Wash and peel potatoes. Slice them very thin (⅛ inch). Use a mandoline for best results.
Step 3 – Make sauce
Melt butter in a saucepan over medium heat. Add onion and garlic. Cook for 2–3 minutes until soft. Add flour and whisk for 1 minute. Slowly pour in milk and cream while whisking. Cook until thick (about 4–5 minutes). Add salt, pepper, and paprika.
Step 4 – Layer potatoes
Layer half the potatoes in the baking dish. Pour half the sauce over them. Sprinkle half the cheddar cheese. Repeat with remaining potatoes, sauce, and cheddar.
Step 5 – Top with parmesan
Sprinkle parmesan cheese on top.
Step 6 – Bake
Cover with foil. Bake for 45 minutes. Remove foil and bake for another 20–25 minutes until top is golden brown and potatoes are fork-tender.
Step 7 – Rest and serve
Let rest for 10 minutes before serving.
Pro Tip
Do not wash sliced potatoes. The starch helps thicken the sauce naturally.