Cook pasta in salted boiling water according to package instructions until al dente. Reserve ½ cup pasta cooking water, then drain and set aside.

Meanwhile, season sliced steak lightly with salt and pepper.

In a large skillet over medium-high heat, heat 1 tablespoon olive oil. Sear steak slices in batches until browned but still slightly pink inside, about 1–2 minutes per side. Remove steak and set aside.

Reduce heat to medium and add remaining tablespoon olive oil. Add minced garlic and cook until fragrant, about 30 seconds.

Stir in soy sauce, honey, sriracha, rice vinegar, crushed red pepper flakes, and broth. Bring to a simmer and cook 1–2 minutes until slightly thickened.

Add butter, stirring until melted into the sauce. Taste and adjust seasoning—add more sriracha for heat, honey for sweetness, or vinegar for brightness.

Return steak slices to the skillet, tossing to coat in sauce.

Add cooked pasta and toss well, adding reserved pasta water a little at a time to create a silky sauce that coats the pasta.

Remove from heat and stir in fresh parsley or cilantro.

Divide pasta between plates or bowls; garnish with green onions and sesame seeds if desired, and serve immediately.