Bring a large pot of salted water to a rolling boil. Add linguine and cook until al dente, about 8-10 minutes. Add broccoli florets in the last 2-3 minutes. Reserve pasta water, then drain.

Cube steak and season with salt, black pepper, smoked paprika, and garlic powder. Heat olive oil in a skillet, add steak cubes, and sear for 3-4 minutes. Let steak rest.

In the same skillet, melt unsalted butter, add minced garlic, sauté for 1-2 minutes. Stir in Dijon mustard, lemon juice, and crushed red pepper flakes.

Add drained linguine and broccoli to the skillet, toss to combine. Add reserved pasta water if sauce is thick. Stir in cooked steak.

Serve hot, sprinkle with Parmesan cheese, and garnish with parsley and chives.