Photo courtesy of Hugh Acheson.
The sweetness and smooth taste of maple syrup combines with fresh herbs to form a mouth-watering sauce for duck, chicken, or even fish. Plus, the blueberries and frisee give this recipe a healthy and nutrient-dense spin.
To make the gastrique, in a small saucepan, combine the maple syrup, vinegar, shallot, and thyme and bring to a boil. Simmer over medium heat, reducing the liquid down to a total of about ¼ cup, for about 10 minutes. Remove from heat, add ½ teaspoon salt, and season with pepper to taste, then strain through a fine mesh sieve, reserving the sauce and discarding the shallot and thyme. Set aside in a warm spot.
Season the duck breasts with ¼ teaspoon of the kosher salt. Score the skin into a grid pattern with a sharp paring knife. This will help render off the duck fat.
Place a large pan over low heat and add the canola oil. Add the duck breasts skin side down and increase the heat to medium. Cook the breasts for 8 minutes, then flip and cook for 3 more minutes. The breasts should be medium-rare, should have rendered off most of their fat, and the skins should be crisp. Remove the breasts from the pan and set them aside to rest.
Add the onion to the duck fat still on the heat and caramelize the onions for 10 minutes over medium heat. Turn the onions once or twice during their cooking. You want to develop color on them but not burn them. Add ¼ teaspoon salt, blueberries, frisee, and the lemon juice to the onions and toss. Turn off heat and just let the pan hang out.
Thinly slice the duck and arrange evenly on plates. Elegantly assemble frisee, blueberries, and onions over the top of the sliced duck and drizzle with the maple gastrique.