Thanks to protein in the eggs and healthy fats in the avocado, this savory salad will keep you going for hours.
Heat 1 inch of water in a small saucepan fitted with a steamer basket over high. Add eggs to steamer basket; cover, and bring to a boil. Steam 6 minutes. Place in an ice bath until chilled, about 5 minutes. Peel eggs; cut in half, and sprinkle evenly with 1/4 teaspoon of the salt.
While eggs cook, combine vinegar and shallot in a small bowl. Let stand 5 minutes. Whisk in mustard, 2 tablespoons of the oil, and 1/8 teaspoon of the salt.
Heat remaining 1 tablespoon oil in a medium nonstick skillet over medium-high. Add mush-rooms; cook, stirring occasion-ally, until tender and browned, 4 to 5 minutes. Remove from heat. Sprinkle with remaining 1/8 tea-spoon salt.
Toss together mushrooms, kale, and frisée in a large bowl. Drizzle with dressing, and top with halved eggs and avocado slices. Serve immediately.