Two-Tone Potato Gratin

This is one of those recipes that was on my blog (may she rest in peace) and you haven’t. stopped. asking. for. it. As you may recall, it was part of a giant Thanksgiving menu, and I am famous (infamous? whichever one is the bad one) for making all of the food, then falling asleep before it even got served. So consider yourselves lucky I stayed up long enough to write this recipe down. Now excuse me while I just close my eyes for a hot minute…

Serves 10-12

Active Time 30 min

Total Time 1 hr 30 min

• 685ml double heavy cream
• 3 cloves garlic, finely chopped
• 1 tablespoon chopped fresh thyme, or 1 teaspoon dried, plus fresh thyme for garnish
• 1 tablespoon chopped fresh sage or 1 teaspoon dried
• 2 teaspoons kosher salt
• 1 teaspoon freshly ground black pepper
• ¼ teaspoon grated nutmeg
• Dash of cayenne pepper
• 200g shredded Gruyère cheese
• 160g finely grated Parmiginiano-Reggiano cheese
• 900g sweet potatoes
• 675g King Edward potatoes

Preheat the oven to 425˚F/220˚C.

In a large bowl, whisk together the cream, garlic, thyme, sage, rosemary, salt, black pepper, nutmeg and cayenne. In a separate bowl, toss together the Gruyère and Parm.

Peel the potatoes, then with a handheld mandolin or a sharp knife, slice the potatoes crosswise into 3-mm-thick rounds. Pour 125ml of the cream mixture into a 23 x 33cm baking dish, then make a layer of potatoes in as nice a pattern as you can, overlapping the slices slightly. (You can do this in individual layers of sweet potatoes and regular potatoes, or mix them up, or do all the sweet then all the regular… basically, you do you!) Drizzle 185 ml of the cream mixture on top and sprinkle with 115g of the cheese mixture. Repeat this layering two more times. Finish with a top layer of potatoes and sprinkle the remaining cheese on top of that. Garnish with fresh thyme.

Cover with foil and bake until bubbling, about 30 minutes. Remove the foil, reduce the oven temperature to 400˚F/200˚C, and bake until the top is golden and bubbling, another 30 minutes. Turn the oven to grill, or pop it under a hot grill until the top is browned, 1 to 2 minutes.

Note | Dried Herbs Are Your Friends

In most cases, you can swap in dried herbs for fresh – just use one-third the amount of dried herbs as you would fresh. So if a recipe call for 3 teaspoons (or 1 tablespoon, because those are the same thing!!) chopped fresh thyme, replace it with 1 teaspoon dried. If I’m honest, I do usually like the taste of fresh herbs better. But when I stood there for like 30 minutes one day picking thyme for a recipe from my first book, I thought, ‘Why the hell did I make people stand there for 30 minutes picking thyme?’

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