Cook the flank steak in a cast iron skillet. Start by heating the olive oil in a cast iron for 1 minute. Generously season the steak with salt and pepper and place in heated pan. Sear it for 4-5 minutes on one side, until the bottom is browned–do not move the steak at all.
Flip the steak, reduce the heat to medium and add the butter. Hold the pan handle with one hand (use a towel, as it will be hot) and tilt the pan slightly, use your other hand to spoon the melted, bubbling butter mixture over the steak repeatedly until it is cooked to medium-rare (about 10 minutes).
Remove the steak from the pan and allow it to rest on a cutting board for at least 5 minutes. Slice against the grain and cut into cubes or slices for your salad.
Chop the tomatoes, onions and make the hard boiled eggs. Mise en place all of your other salad ingredients: blue cheese, leafy greens and pine nuts. Make the dressing by placing all ingredients in the food processor and add water by the tablespoon to get it to the consistency you like (it should be pourable). Season with salt and pepper.
Assemble your salad with all of the fixings and cubed steak and pour dressing on last. Enjoy!