Bring a large pot of salted water to boil.
Pat the flank steak dry with paper towels and season with salt and pepper on both sides.
Heat the neutral oil in a large pan to medium-high heat. Once shimmering, add the flank steak and sear for 4 minutes on the first side then 3 minutes on the other side. Remove the steak to a cutting board and tent with foil. After 10 minutes of resting, thinly slice the steak against the grain into bite sized pieces. Tent with foil to keep warm and set aside.
Add the mushrooms to the same pan. Sear mushrooms until they release their water and brown (about 3-5 minutes). Once browned season with a bit of salt and pepper and remove mushrooms to a plate and tent with foil.
Turn the heat to medium-low and add in the butter, onion, and a pinch of salt. Saute for 5-7 minutes or until translucent and soft. After the onions are soft, add the tomato paste and cook for 3 minutes stirring frequently.
At this point begin boiling the pasta to 1 minute less than al dente.
Add the bourbon and beef stock and turn the heat to high. With a wooden spoon scrape the brown bits off the bottom of the pan. Once the liquid has reduced by about half (about 2-3 minutes) turn the heat down to medium and add 1 cup of pasta water.
Add the cream and bring to a simmer to allow the sauce to thicken. Taste test and season with salt and pepper to taste.
Add the mushrooms and sliced steak to the sauce along with the pasta. Mix well and cook until the pasta is just al dente then turn off the heat and remove the pan from the stovetop.
Add the cheese along with the parsley and mix well. If the sauce is too dry add more of the reserved pasta water, a bit at a time, to get the consistency just right. Enjoy!