Makes 4 servings
- 4 small sweet potatoes, scrubbed
- 3 tablespoons extra-virgin olive oil, divided use
- Kosher salt, to taste
- 2 tablespoons unsalted butter
- 3 medium yellow onions, thinly sliced
- Freshly ground black pepper, to taste
- 1 lb 8 oz mixed mushrooms, like oyster, shiitake, or cremini, cut into bite-sized pieces
- 2 tablespoons minced garlic
- 2 tablespoons dry white wine
- 2 teaspoons chopped thyme, plus more as needed
- 1/2 cup crème fraîche
- Preheat the oven to 350°F. Poke the potatoes all over with a fork, then drizzle with 1 tablespoon of the oil. Rub the potatoes all over, sprinkle with salt, and transfer to a baking sheet. Bake until the potatoes are tender when pierced with a knife, 45 minutes to 1 hour.
- Meanwhile, heat the butter in a large skillet over medium heat. Add the onions and a pinch of salt, and cook, stirring occasionally, until the onions are very lightly browned all over, about 15 minutes. Lower the heat to medium-low and cook, stirring frequently, until the onions are deeply browned, about 40 minutes. If any dry spots in the pan begin to burn, add some water to moisten the pan. Transfer the onions to a bowl, and wipe out the pan.
- Return the pan to medium heat and add the remaining 2 tablespoons olive oil. Add the mushrooms and a pinch of salt, working in batches, if needed, and cook without stirring until the edges are browned and well-seared, about 4 minutes. Continue cooking, stirring occasionally, until the mushrooms are well-browned all over, about 8 minutes. Stir in the garlic and a pinch of pepper and cook until fragrant, about 30 seconds. Add the wine and cook until the wine has reduced and the pan is dry, about 1 minute. Remove from the heat and stir in the thyme.
- To serve, slice each potato down the center and push the two sides apart slightly. Use a fork to gently mash the inside of the potato. Top each potato with 2 tablespoons of crème fraiche. Add a layer of caramelized onions, then top with the mushrooms. Sprinkle with additional thyme before serving, if you like.