15-Minute Lemon Garlic Butter Steak with Spinach

(750g) flank steak, sliced against the grain

fresh spinach

butter or ghee (or less if you want)

garlic cloves, minced

Juice of 1/2 lemon 

low-sodium beef broth

chopped parsley

chopped chives

 teaspoon crushed red pepper flakes

Salt and fresh cracked pepper,