Cook Pasta: Bring a large pot of salted water to a rolling boil. Add spaghetti and cook for 8-10 minutes until al dente. Reserve ½ cup of starchy pasta water before draining. Toss pasta with a tablespoon of butter to enhance richness.

Prepare Steak: Pat steak cubes dry. In a bowl, combine cubes with salt, pepper, soy sauce, and optional cornstarch. Marinate for about 10 minutes.

Sear Steak: Heat a skillet over high heat and add olive oil. Once hot, add marinated steak, searing for 2-3 minutes on each side until caramelized. Remove from skillet.

Make Sauce: In the same skillet, reduce heat to medium. Sauté minced garlic until fragrant, then add soy sauce, honey, sriracha, rice vinegar, sesame oil, red pepper flakes, and reserved water. Simmer until sauce thickens.

Combine: Add cooked spaghetti back into the skillet, tossing to coat in sauce. If too thick, add reserved pasta water. Return seared steak to skillet and stir together for about one minute.

Serve: Plate the pasta, garnishing with toasted sesame seeds and fresh herbs. Enjoy warm!