Potatoes Au Gratin with Gruyere and Cream

Ingredients

• 3 lb Yukon Gold potatoes, peeled
• 2 cups heavy cream
• 1 cup whole milk
• 4 cloves garlic, smashed
• 2 sprigs fresh thyme
• 2 tsp kosher salt
• 1 tsp black pepper
• 1/4 tsp ground nutmeg
• 2 cups shredded Gruyere cheese
• 1/2 cup grated Parmesan cheese
• 2 tbsp unsalted butter

Before you cook

• Peel the potatoes and slice them 1/8 inch thick.
• Smash the garlic cloves with the flat of a knife.
• Shred the Gruyere and grate the Parmesan.
• Rub a 2-quart gratin dish or 9-by-13-inch pan with the butter.

Steps

1. Heat the oven to 375 degrees Fahrenheit.
2. Combine the cream, milk, smashed garlic, thyme sprigs, salt, pepper, and nutmeg in a wide pot.
3. Bring the cream to a bare simmer over medium heat.
4. Slide the potato slices into the pot and stir gently so they separate.
5. Simmer for 10 minutes, stirring carefully two or three times, until the potatoes are just tender at the edges and the cream has thickened from the released starch.
6. Fish out the garlic cloves and the thyme sprigs and throw them away.
7. Lift half the potato slices into the buttered dish with a slotted spoon and spread them flat.
8. Scatter 1 cup of the Gruyere over that layer.
9. Add the rest of the potatoes in an even layer.
10. Pour the thickened cream from the pot over everything, pressing the top down so the liquid rises to the surface.
11. Scatter the remaining Gruyere and all the Parmesan over the top.
12. Bake uncovered for 45 minutes, until the top is bronzed and the cream bubbles slowly at the sides.
13. If the top has not browned enough, run it under the broiler for 2 minutes and watch it closely.
14. Rest the gratin for 20 minutes before cutting, so the layers hold together.