In a bowl, whisk the anchovy paste, Dijon mustard, 3 tbsp olives, red wine vinegar, olive oil, and parmigiana together. Coat the frisée greens with the dressing. Add halved cherry tomatoes and set aside.
Salt the the flat iron steak liberally on both sides. In a heavy-bottom pan heated to medium-high heat, sear the steak for 4-5 minutes. Flip and cook for another 4-5 minutes. Remove from heat and let rest for 5 minutes. Slice the flat iron against the grain and top with the salad. Finish with fresh cracked black pepper.