This simple recipe was inspired by the Argentine chef Francis Mallmann, whose cookbook, Seven Fires: Grilling the Argentine Way, is a fascinating look at cooking with fire – over it, around it, and even in it, as I do here. The end result might look a little scary at first, but the flavor you will achieve is undeniable.
Throw your sweet potatoes in the fire in your oven. No, seriously. OK, fine, set them in the ashes at the edge of your fire. Turn them periodically. They are going to blacken and char and feel crispy and crunchy when you touch them. That is OK. Let them cook that way for 45 minutes to an hour. Transfer the sweet potatoes to a large piece of foil, wrap them tightly, and place them back on the edge of the fire to finish cooking. Allow them to steam in the foil until completely tender, 15 to 30 minutes.
Meanwhile, make your compound butter. Heat the vegetable oil in a medium-sized skillet. When it begins to shimmer, add the onion, season with salt and pepper, and sweat until just translucent, 2-3 minutes. Add the sage and cook for another 3-4 minutes, until the pan is very aromatic and everything is soft. Remove from the heat and allow to cool to room temperature. Transfer the onion mixture to the bowl of a food processor, along with the butter and honey. Season with salt and pepper. Pulse until well combined. Scoop the butter out into a bowl and place in the fridge to firm up.
When the potatoes are soft, remove from the foil. Cut a lengthwise slit in the top of each potato and squeeze them open to expose the brilliant orange flesh. Season with salt and pepper. Remove your butter from the fridge, place dollops on top of the sweet potatoes, and serve. The rich, slightly smoky sweetness will complement anything savory you’ve roasted in your oven, particularly game meats or turkey.