In a medium bowl, whisk together soy sauce, chicken stock, honey, vinegar, brown sugar, garlic, sesame oil, cornstarch, Sriracha, ginger, red pepper flakes and 1/4 cup water; set aside.
Heat olive oil in a large cast iron skillet over medium high heat. Add steak and cook, flipping once, until browned, about 3-4 minutes.
Stir in broccoli and soy sauce mixture until tender and slightly thickened, about 3-4 minutes.