Season the steak with salt and pepper.
Heat the grill on high heat, or heat ghee in a skillet over high heat on the stove top. Cook steak for 4-6 minutes per side depending on your preferred level of doneness.
Transfer the steak to a cutting board and cover with an aluminum foil. Make the pasta while the steak rests.
Heat ghee in a large, wide skillet over medium heat.
Add onion and garlic to the pan and stir cooking for 2-3 minutes until the onion is translucent.
Pour in broth, milk, salt, pepper, and crushed red pepper flakes. Add the dry pasta and submerge in the liquid.
Turn up the heat to bring to a boil, then reduce to simmer. Cook for 7-12 minutes (depending on the cook time of your pasta), while stirring occasionally to prevent from sticking. The pasta should cook through and the sauce should reduce and thicken. If too much liquid cooks off, you can add more milk.
Optional: The sauce might be thin depending on what milk you use. If you want to thicken the sauce, whisk together arrowroot starch and 1 tbsp of water in a small bowl and stir into the pan.
Stir in nutritional yeast and frozen peas for one minute. Taste to add more salt, ground black pepper, or crushed red pepper flakes. Turn off heat.
Slice the steak thinly against the grain.
Serve pasta on a plate, topped with a few slices of the steak. Sprinkle with parsley, for garnish.