Brown Butter Rosemary Roasted Sweet Potatoes Recipe

We all face the same question each year as Thanksgiving approaches: Do we stick with the classics or do something a little different? And, if we do something different, just how different do we want to get? I came up with a few twists on the classic sweet potato. Here’s a riff on the traditional, but you can also try this savory miso-scallion version or a spicy, smoky sweet potato dish.

In each case, I stick with a technique Kenji has written about before, which calls for par-cooking the potatoes in 160°F (70°C) water. This temperature helps maximize the transformation of complex starches into simple sugars. Above 170°F (77°C), the enzymes that do the heavy lifting shut down, leading to less sweet and flavorful potatoes. Then the potatoes are tossed in oil and roasted until they're nicely browned and slightly crisp in spots.

These potatoes are bathed in a rich and buttery sauce that's been infused with rosemary and a base note of savory chicken stock. I make it by melting the butter in a saucepan, then cooking it until the milk solids turn a deep hazelnut color. As soon as it reaches that brown shade, I remove it from the heat and throw in sprigs of fresh rosemary. They'll sizzle and fry in the hot butter, releasing their woodsy-piney aroma into it (and into your kitchen—it smells great).

I don't stop there, though. After that, I pour in a small amount of chicken stock that I've spiked with unflavored gelatin. The gelatin adds a rich viscosity to the stock (especially important if your stock isn't homemade), which ensures that the sauce doesn't end up with a thin, watery texture.

I return it to the heat at this point and simmer it until the stock is further reduced and syrupy, with a deep, meaty flavor. Then I fish out and discard the rosemary sprigs. To balance out all that richness, I hit it with a splash of fresh lemon juice, plus plenty of salt so the flavor really pops.

When the potatoes are ready, I just toss them with the sauce, and I'm done.