Impossible Jardiniere Burger

“Impossible: The Cookbook” recommends this recipe from chef Traci Des Jardins as the ideal starting point for people cooking with Impossible Burger for the first time. It’s easy to see why: The burger emerges juicy, with a beautiful seared crust, and it’s hard to go wrong with avocado and caramelized onions. For many Bay Area residents, it might also be a nostalgic taste of Des Jardins’ shuttered Hayes Valley restaurant Jardiniere.

2 tablespoons extra-virgin olive oil

3 yellow onions, thinly sliced

½ cup mayonnaise, preferably plant-based

3 tablespoons Dijon mustard

2 avocados, pitted and peeled

Kosher salt

1½ pounds Impossible Burger

Ground black pepper

6 ounces Gruyere or plant-based cheese, sliced (optional) 6 soft hamburger buns, split

4 tablespoons unsalted butter or plant-based butter spread, at room temperature

6 romaine or Little Gem lettuce leaves, torn into bun-size

pieces

16 cornichons, thinly sliced lengthwise

Instructions: In a heavy medium skillet over low heat, warm the oil. Add the onions and cook, stirring occasionally, until they are completely soft and slightly caramelized, about 50 minutes. Cover the skillet for the first half of cooking to allow the onions to soften, then remove the cover about halfway through.

Meanwhile, in a small bowl, stir together the mayonnaise and mustard. In another small bowl, mash the avocados with a pinch of salt. Divide the Impossible Burger into six equal portions (4 ounces each) and form into patties ½-inch thick.

Preheat a grill for direct cooking over high heat (450 degrees), or preheat a stove-top grill pan over medium-high heat. If using a grill, brush the grates clean.

Season both sides of the patties with a generous sprinkling of kosher salt and black pepper. Cook the burgers over direct heat on the grill or in the pan until grill-marked on the bottom, about 3 minutes. Turn the burgers, layer the cheese slices on the upturned cooked sides, and cook another 1½ minutes for medium-rare or 2 minutes for medium. Transfer the patties to a platter.

Spread the cut sides of the buns with the butter and toast on the grill or in the grill pan until golden brown, about 30 seconds. Transfer the toasted buns to a platter or cutting board.

To assemble, spread the toasted sides of each bun with some of the Dijon mixture. Spread the top bun with some of the avocado. Layer the bottom bun with cornichons, a couple of pieces of lettuce, a patty and a large spoonful of caramelized onions. Top with the top bun and serve at once.