1 cup packed fresh flat-leaf parsley leaves, chopped, (option: reserve 2 tsp for grapefruit-olive side)
4 to 6 sprigs lemon thyme leaves, chopped
Zest of one grapefruit (take care not to include the bitter pith); option: supreme* the grapefruit wedges and cut in 1/2 and reserve for grapefruit-olive side
Zest and juice of one lime
1/2 cup extra-virgin olive oil
2 cloves garlic, peeled and minced
1 teaspoon harissa or sriracha chili paste
Optional: 1/2 cup chopped Kalamata olives, for a grapefruit-olive side)
Optional: Butter lettuce washed and removed into cups
Optional: Chopped tomatoes
Season steak with 1 tsp salt and pepper and let it come to room temperature.
For the gremolata, combine pistachios, parsley, lemon thyme, grapefruit zest, lime juice, olive oil, garlic, chili paste, and remaining salt in a medium-sized bowl.
Let the mixture rest for 30 to 60 minutes at room temperature. Alternatively, you can refrigerate for 24 hours and bring to room temperature prior to serving.
Preheat a grill pan over medium-high heat. Grill steak until dark grill marks develop, which should take around 3 to 5 minutes. Turn and grill on the second side another 3 or 4 minutes; the steak should still be pink in the middle.
Remove to a cutting board, cover with foil, and rest for 5 minutes. Drizzle a good amount of the gremolata over the steak before slicing, reserving a portion for serving.
Slice the steak across the grain and serve in one of the following ways:
Side grapefruit-olive option: Mix grapefruit wedges with chopped kalamata and 2 tsp chopped parsley, season with salt and pepper to taste.
Lettuce cups option: Chop steak into 1/4″ cubes and serve a few pieces at a time inside butter lettuce leaves “cups” along with chopped tomatoes and a drizzle more of gremolata.
*How to supreme: http://www.marthastewart.com/1049240/supreming-grapefruit