Inspired by the Senegalese poulet yassa—a dish of chicken and caramelized onion with lemony mustard sauce—this recipe pairs mildly sweet, earthy, and nutty parsnips with a juicy and flavorful marinade of peanut oil, black pepper, onions, mustard seeds, garlic, habanero, and Dijon mustard. The parsnips are then topped with seasoned caramelized onions and garnished with peanuts and thyme, adding to the layers and levels of deliciousness. This is a richly flavored
side dish that should be served alongside a neutral starch such as rice or mashed potatoes to balance its intensity.
1 tablespoon plus 1 teaspoon kosher salt
2 pounds parsnips, peeled
½ cup fresh lemon juice
¼ cup plus 2 tablespoons peanut oil
Freshly ground black pepper
2 large Vidalia or yellow onions, sliced into ½-inch rings
1 teaspoon yellow mustard seeds
1 teaspoon minced garlic
⅛ teaspoon minced habanero chile, or to taste
1 tablespoon Dijon mustard
¼ cup crushed peanuts
1 tablespoon fresh thyme leaves
In a large pot, bring 3 quarts water to a boil over high heat. Add 1 tablespoon of the salt and the parsnips to the water and cook until starting to soften, 4 to 5 minutes. Drain the parsnips and set aside to cool slightly.
In a large bowl or baking dish, combine the lemon juice, 6 tablespoons water, ¼ cup of the peanut oil, the remaining 1 teaspoon salt, and a few turns of pepper. Mix well with a fork to combine. Once the parsnips are cool enough to handle, cut them in half lengthwise and add them to the bowl with the marinade. Add the onions and toss well to ensure that all the vegetables are coated. Cover and refrigerate for at least 2 hours or up to overnight, tossing the vegetables every 30 minutes or so for the first 2 hours.
In a large sauté pan, warm the remaining 2 tablespoons peanut oil over medium-low heat. Remove the onions from the marinade and add them to the pan. Sauté, stirring frequently, until deep golden brown and soft, 30 to 45 minutes. Add the mustard seeds, garlic, and habanero and sauté, stirring well, until the garlic smells fragrant, 3 to 4 minutes. Scrape the vegetables into a bowl.
Preheat the oven to 450°F. Line a large rimmed baking sheet with parchment paper.
Remove the parsnips from the marinade and place them cut-side up on the prepared baking sheet (reserve the marinade in the bowl). Roast the parsnips, gently stirring every 10 minutes, until fork-tender and starting to brown, about 30 minutes.
In a blender, combine ½ cup of the onion mixture, the reserved marinade, and the mustard and blend until creamy. Pour the contents of the blender into a small pan and simmer over medium heat, stirring often, until the sauce starts to thicken, 3 to 5 minutes.
To serve, spread the onion-mustard sauce over a serving plate and place the parsnips over the sauce, cut-side up. Garnish with the remaining onion-mustard sauce, onions, the peanuts, and thyme and serve family-style.