There are thoughts that roll around inside a professional recipe writer’s head on a seasonal cycle: “How many more words can one write about hamburgers?” “Can we just agree that spatchcocking is the best way to roast a turkey?” “Doesn’t everyone in the world know how to boil an egg by now?”
(The responses, in order: “I have not yet found the limit,” “yes, please,” and “they sure think so.”)
The words rolling around in mine about a month ago: “There are no new ways to roast potatoes.”
Years ago, I developed a recipe for ultracrispy roasted potatoes that uses a classic British approach. First, you boil potatoes in salted water until tender, then you toss them roughly in a bowl with fat (preferably drippings from a roast), causing a starchy slurry to form on the surface. As the potatoes roast, that slurry dries and crisps, forming a craggy crust that give the potatoes a hefty crunch.
A few years after that, I realized that the phrase “ultracrispy” was relative, and even those potatoes could be improved upon. So I developed a recipe that I modestly called “The Best Crispy Roast Potatoes Ever” for the website Serious Eats. I added a touch of baking soda to the initial boil, raising the pH of the water. This causes pectin — the polysaccharide glue that holds plant cells together — to break down more rapidly. In turn, the surfaces of the potatoes become extra-starchy, which increases crispness significantly.
So where could I go from “best”?
Recently I’ve had pizza on the mind — specifically Detroit-style pizza, and even more specifically the crisp cheese crust that develops around the rim of the blue steel baking tray. If you’ve ever had frico, those crisp disks of fried Parmesan that crunch as you bite into them and dissolve into a wash of nutty, savory flavor on your tongue, you know what I’m talking about.
How great would it be to combine roast potatoes with a crispy cheese crust?
First I tried boiling potatoes (russets for their starchiness) in alkaline water (salted with 1/4 teaspoon of baking soda added per quart) that I flavored with peppercorns, garlic and herbs (I’ve found that boiling with aromatics is the best way to get flavor that really sticks to potatoes).
Next, I transferred the potatoes to a cast-iron skillet and sprinkled grated cheese along the edges of the pan, just as I would treat the dough in a Detroit pizza. The results were promising, but far from what I was looking for: The cheese formed more of a leathery sheath than a truly crisp crust, while packing the potatoes into the pan reduced the surface area for crusting.
Roasting them spread out on a parchment-lined baking sheet would be the way to go.
After tweaking a bit more, I landed on adding grated Parmesan directly to the bowl as I tossed the hot, parboiled potatoes with melted butter, which complements the flavor of the cheese better than olive oil or animal fat. By doing this, the Parmesan melts slightly, combining with the starchy slurry and forming an even coating over every potato piece.
The batches I’ve been pulling from the oven recently are spectacular. The cheese crust shatters just like frico, but with a heftier crunch, revealing a fluffy potato interior. The combination of savory crust and moist interior remind me of seasoned frozen curly fries (the best expression of frozen potatoes), if seasoned frozen curly fries managed to pull off the painfully-sophisticated-yet-casual look.
As for the recipe title, I’m not really sure where I can go from “best,” so enjoy these extra-crispy Parmesan-crusted roasted potatoes.
Until next time, potato. And there will be a next time.