Heat the butter in a large heavy duty skillet over medium low heat until lightly browned but not black (this just adds flavor to the steak).
Cut the steak into bite sized pieces. Turn the heat up (higher heat is good!) and add the steak to the butter in the skillet. Let the steak sit in the pan for about a minute without stirring - this helps it get a nice sear on one side, like you see in the picture. Flip the steak pieces and cook for another minute or two, until both sides are well-seared. This should only take 2-3 minutes - because of the size of the steak pieces, you really only need to sear the outside and the insides will continue to cook just enough once you remove from the pan.
Remove the skillet from heat, transfer the steak to a bowl, and wipe the skillet with a paper towel to remove excess grease. Add the sauce to the pan. Stir in the steak and simmer for 5-10 minutes while you prepare the zucchini noodles or pasta.
Spiralize or cut the zucchini into noodles, or cook the pasta, depending on what you're using. Top with the sauce and sprinkle with Parmesan and parsley. Serve immediately.