Bring a large pot of salted water to a boil and cook the linguine according to package directions until al dente.
While pasta cooks, season the chicken breast with half of the salt and pepper, then sear in a large skillet over medium-high heat until golden and cooked through.
Remove the chicken from the skillet and set aside to rest before slicing into thin strips.
In the same skillet, melt the ghee and add the sliced cremini mushrooms, sautéing until they release their moisture and turn golden brown.
Add the minced garlic to the mushrooms and cook for 1 minute until fragrant, being careful not to burn it.
Drain the pasta, reserving 2 tablespoons of the starchy cooking water.
Add the pasta, sliced chicken, and reserved water to the skillet with the mushrooms, tossing everything together over low heat.
Remove from heat and drizzle with truffle oil, then sprinkle with parmesan cheese, fresh parsley, and the remaining salt and pepper.
Toss one final time to ensure the sauce is velvety and coats every strand of pasta before serving.