Kat Can Cook

0 In a large bowl, toss the sliced beef with 1 teaspoon of salt and ¼ teaspoon of cracked pepper. 
1 To a large skillet over medium-high heat, add the oil.  When the foam subsides, working in batches, add the beef and cook, flipping once, until browned, 1–2 minutes total.
2 Transfer the meat to a plate and set aside, making sure to get any juices that are still in the pan (their will be juices when you dice the beef later, so don’t fret if there isn’t much to work with).  
3 Let the beef rest for 10 minutes before dicing the beef slices into 2 inch cubes.  Set aside.
4 To the skillet, add the butter followed by the onion and cook until slightly softened, about 1 minute.
5 Add the stock, vinegar, and sugar or honey, and cook, stirring to scrape up any browned bits until reduced slightly, about 1 minute.
6 Stir in the creme fraiche, Worcestershire, and dijon mustard. 
7 Turn the heat to low and continue cooking, stirring occasionally, until the sauce is just heated through (do not boil, or it will curdle), 2–3 minutes more. 
8 Taste and add more salt and/or vinegar if the sauce needs it (I usually do). 
9 Remove from the heat, add the reserved beef and any juices, and stir to combine.
10 Serve over egg noodles or rigatoni and garnish with plenty of parsley.