3 tablespoons maple syrup.Shape pike mixture into 16 ovals (about 1/4 cup each) by using a spoon to press and smooth mixture against a second spoon.
Cook quenelles, in batches if necessary, in water, flipping and bobbing to submerge occasionally, until cooked through, about 15 minutes, adjusting heat as needed to maintain 170°F.. Heat remaining 1 1/2 tablespoons oil in a large skillet over medium-high.Add mushrooms; cook, stirring occasionally, until lightly browned and tender, 6 to 8 minutes.
Sprinkle with remaining 1/4 teaspoon salt and set aside.. Preheat broiler to high with oven rack 6 inches from heat.Place 2 quenelles in each of 8 (12-ounce) gratin dishes and spoon 1/2 cup lobster sauce into each dish over quenelles.