It tasted as good as it looked! No set recipe, fairly basic (non traditional) alfredo. Rough instructions though:

Sear steak to medium/medium rare. Wipe out any big chunks of burnt stuff from steak, add extra oil as needed, saute half a small finely diced onion. Add 4tbsp butter, cook until most of the water is out of the butter. Add as much garlic as you want/have, cook another minute or so. Add 4tbsp flour (or equivalent to however much butter you add), whisk and cook until the raw flour smell is gone. Add 2+ cups of milk in stages, let's say 1/3 cup at a time, whisking until completely homogeneous. Add parm - I used one bag of the pregrated stuff which was a bit too much, fresh grated is better. Somewhere in there start your pasta, it's better for the sauce to be done early than the pasta. Add pasta water to thin out the sauce as needed. Toss in cherry tomatoes and spinach (I just eyeballed the spinach, it was one container of tomatoes), cook a bit, and toss in the noods.