Cook rotini pasta in a large pot of salted boiling water according to package directions until al dente.
In a small bowl, whisk together honey, soy sauce, minced garlic, grated ginger, and cornstarch until smooth.
Season steak cubes with salt and black pepper.
Heat vegetable oil in a large skillet or wok over medium-high heat.
Sear the steak cubes in batches until browned on all sides, approximately 2-3 minutes per batch, then remove from skillet and set aside.
Wipe out excess oil and melt butter in the same skillet.
Pour the honey-soy mixture into the skillet and simmer over medium heat until the sauce begins to thicken, about 2 minutes.
Return the steak bites to the skillet and toss to coat thoroughly in the glaze.
Drain the pasta and add it directly to the skillet, tossing until the rotini is evenly coated and the sauce is sticky.
Garnish with red pepper flakes and sliced green onions before serving.