Cheesy Au Gratin Potatoes
A classic, indulgent potato gratin that layers thinly sliced potatoes with a lusciously seasoned cream and a golden, cheesy crust.
Servings: 4 servings
Calories: 320kcal
Equipment
- 9x13 inch baking dish - for even layering and browning
- Mandoline or sharp chef's knife - for precise, uniform slices
- Heavy saucepan - to make the cream sauce
- Microplane grater - to shred cheese finely for melting
Ingredients
- 900 g 2 lb Russet or Yukon Gold potatoes
- 480 ml 2 cups heavy cream
- 240 ml 1 cup whole milk
- 100 g 1 cup Gruyere cheese, grated
- 80 g 3/4 cup sharp cheddar, grated
- 2 cloves garlic minced
- 30 g 2 tbsp unsalted butter
- 8 g 1 tsp kosher salt
- 2 g 1/2 tsp freshly ground black pepper
- 1 g 1/4 tsp ground nutmeg
Instructions
- Preheat the oven to 190C (375F). Butter the baking dish so the first potatoes slide and the edges brown evenly.
- Thinly slice potatoes 2-3 mm (1/16-1/8 inch) using a mandoline for consistent cooking; you want tender sheets that still hold shape.
- In a saucepan, sweat minced garlic in butter over medium heat until fragrant, about 30 seconds, then add cream and milk.
- Bring the cream to a gentle simmer - small bubbles around the edge - then whisk in salt, pepper and nutmeg. Do not boil; simmering concentrates flavor without breaking the cream.
- Remove the pan from heat and stir in half the grated cheeses until mostly melted, creating a glossy, seasoned cream.
- Arrange a single layer of potato slices in the dish, slightly overlapping, then spoon a third of the cream mixture over and sprinkle a touch of cheese. The cream should just cover the potatoes, creating steam and richness.
- Repeat two more layers, finishing with the remaining cheese on top for a deeply browned crust that crackles when cut.
- Cover loosely with foil and bake for 35 minutes, then remove foil and bake another 20-30 minutes until the top is golden and bubbling and a knife slides through the center easily.
- Let rest 10-15 minutes; the gratin will set and the textures will meld. You should smell butter, toasted cheese and a subtle nutmeg aroma.
Notes
- Make-ahead: Assemble, refrigerate up to 24 hours, then bake straight from the fridge adding 10-15 minutes.
- Cheese swap: Use Comté or Emmental for similar melt and flavor if Gruyere is unavailable.
- Crispier top: Toss a tablespoon of panko with melted butter and sprinkle before the final 15 minutes of baking.