For the butter:
In a food processor add, butter basil, garlic, salt and pepper. Pulse a few times until well combined. Add lemon juice and drizzle oil. Pulse again. Add cheese, pistachios and red pepper flakes. Remove from processor with a rubber spatula onto a sheet of parchment paper and shape into a log. Place in the refrigerator and allow to set for at least 30 minutes.
For the steak:
Preheat grill to medium.
Drizzle the steaks with olive oil. Put on the grill, and while cooking season with sea salt and black pepper, to taste. Cook for 3 to 4 minutes, then flip and season with salt and pepper, to taste. Grill for another 3 to 4 minutes. Remove from the grill to a platter and allow to rest for a few minutes. Slice disks of butter, put on steaks while still hot and serve.