In a medium serving bowl, combine the pineapple, bell pepper, onion, and cilantro. Add salt and pepper, and stir to combine. Set aside.

Add butter to a cast iron skillet. Cut steak in half, and rub with salt and pepper generously. Broil steaks for 3 to 4 minutes on each side until desired temp is reached.

Slice steak into long strips and add to flour tortilla. Top tacos with pineapple salsa and enjoy.