How to Make It
Preheat oven to 450°F. Combine potatoes and 1 tablespoon salt in a medium pot and cover with cold water by 1 inch. Bring to a boil over high. Reduce heat to medium and simmer until potatoes are tender when pierced with a sharp knife, 12 to 15 minutes. Drain potatoes and return them to pot.
Pour 1 tablespoon oil on a rimmed baking sheet and scatter potatoes over it. Using a glass or flat-bottomed measuring cup, gently flatten each potato. Turn potatoes to coat in oil and season with ½ teaspoon each salt and pepper. Scatter ¼ cup cheese over potatoes. Bake until golden and crispy, 18 to 20 minutes.
Meanwhile, heat 1 tablespoon oil in a large skillet over medium-high. Season steak with 1 teaspoon salt and ½ teaspoon pepper. Add steak to skillet and cook, turning once, until deeply browned, about 5 minutes per side for medium-rare. Let rest for 5 minutes before slicing.
Whisk together lemon zest and juice and remaining ¼ cup oil, ¼ cup cheese, and ¼ teaspoon each salt and pepper in a medium bowl. Place greens in a large bowl; drizzle with half of the dressing and toss to coat. Transfer to a platter, top with warm potatoes and steak, and drizzle with remaining dressing.