In a medium bowl, whisk together the soy sauce, hot sauce, lemon juice, and black pepper. Add the steak bites and marinate for 15 minutes.

Heat the olive oil in a large cast-iron skillet over high heat until shimmering.

Drain the steak bites from the marinade, reserving the liquid. Sear the steak in a single layer for 2 minutes per side until a brown crust forms. Work in batches to avoid overcrowding. Remove steak from the skillet and set aside.

Reduce the heat to medium. Add 2 tablespoons of butter and the minced garlic to the same skillet. Sauté for 1 minute until fragrant.

Pour in the reserved marinade juices and beef broth. Bring to a simmer for 2 minutes to reduce slightly.

Add the zucchini noodles to the skillet. Toss frequently for 2 to 3 minutes until tender-crisp. Do not overcook to prevent sogginess.

Return the steak bites to the pan and add the remaining 1 tablespoon of butter and red pepper flakes. Toss to combine and heat through for 1 minute.

Garnish with fresh parsley and serve immediately.