Scalloped Potato Gratin

1. Prepare Baking Sheet

Grease a 17-by-13-inch baking sheet with butter, using a brush to coat every nook and cranny. Set aside some foil for covering the dish later.

2. Simmer Cream Mixture

In a medium pot, combine heavy cream, sage leaves, grated garlic, grated nutmeg, and a pinch of salt. Allow to simmer gently for about 15 minutes until it reduces by a quarter.

3. Temper Eggs

In a large heatproof bowl, lightly beat the eggs. Gradually introduce the hot cream mixture to the eggs, whisking constantly to temper them.

4. Slice and Layer Potatoes

Using a mandoline or a sharp knife, slice the russet potatoes thinly. Arrange the slices on the prepared baking sheet, seasoning with salt and pepper as you layer.

5. Add Egg Mixture and Cheese

Pour the tempered egg mixture over the layered potatoes, ensuring it seeps into every layer. Sprinkle grated Gruyère cheese over the top.

6. Bake Covered

Cover the potatoes with the buttered foil prepared earlier and bake in a preheated oven for 20 minutes, allowing the potatoes to become tender.

7. Final Bake

Remove the foil and continue to bake uncovered for another 25-30 minutes until the gratin is golden brown and bubbling at the edges.

8. Serve

Let the Scalloped Potato Gratin stand for a moment after baking, then serve it hot.