This dish, sweet with a tart edge, is similar in construction to the potato gratin of France. It is served with a sauce of maple syrup, lime juice, cracked pepper, and herbs. The dish improves as it sits; do not hesitate to make ahead and reheat in a low oven the next day.
1/2 cup fresh lime juice
1/2 cup water
1 cup plus 1 teaspoon pure maple syrup
1/2 tablespoon oil
3 medium-large sweet potatoes (2 1/2 - 3 pounds total), peeled and cut into paper-thin slices
Sea Salt, such as Sriracha Lime Sea Salt, Himalayan Pink Sea Salt or Grey Sea Salt
2 large white or red onions (about 2 pounds total), cut into paper-thin slices
1 teaspoon (packed) grated lime zest
1 1/2 cups fresh bread crumbs
1/2 teaspoon coarsely ground black pepper, such as Lampung or Sarawak
2 teaspoons chopped fresh marjoram or sage or 1 teaspoon dried
Preheat the oven to 350 degrees F. Place 2 tablespoons lime juice in a small nonreactive saucepan along with water and 1 teaspoon maple syrup. Bring to a boil, lower heat, and reduce to 1/2 cup, 10 to 15 minutes depending on size of pan. Set aside or refrigerate until ready to use.
Lightly coat a 13-by-9-inch baking dish with oil. Layer one-third sweet potato slices in dish and season lightly with sea salt. Arrange half onion slices over potatoes and season lightly with sea salt. Make another layer of potatoes, a layer of the remaining onion and finally a layer of remaining potatoes, seasoning each layer lightly with sea salt.
Add lime zest and a pinch of sea salt to the reduced lime-maple mixture. Whisk and pour over the potatoes and onions. Scatter bread crumbs evenly over the top. Cover and bake 1/2 hour. Uncover and continue baking 45 minutes to 1 hour more, or until crumbs are golden and crusty and tip of a sharp knife passes easily through potatoes; they should be tender. Let dish stand 15-20 minutes to set before serving or cool to room temperature and refrigerate until ready to use.
To serve, add remaining 1 cup maple syrup to reserved lime juice along with pepper and herb of choice. Gently heat without boiling and remove from stove. Serve the dish and spoon the sauce over each portion.
Recipe © Deirdre Davis 2015