Chicken- Cut chicken breast into halves or thirds, then season with seasoning salt, and a bit of salt and pepper. In a nonstick skillet, fry the chicken on medium-low heat with 4 tbsp of butter until cooked through. Once done, set aside.

Pasta - Cook Linguine pasta according to the instructions on the box. Instead of rinsing the pasta with water, toss it with some olive oil. Once done, set it aside.

Roux - In the same pan used to sear the chicken, add chopped onion, mushrooms (optional), and 1/3 cup butter. Sauté the onion until soft and well cooked, then add minced garlic. Continue cooking until everything is well sautéed.
Add 1/2 cup flour, and whisk until it turns slightly beige and has a nutty smell (about 2 minutes). Slowly add one cup of cream, then 3 cups of milk, whisking constantly until the mixture thickens. Adjust the thickness of the mixture by adding more or less milk.

Finally, add 1 tsp of salt, 1/2 tsp of pepper, and 1/8 cup of Parmesan cheese. The sauce should have a slightly salty taste, but will balance well with the pasta.

Assemble - Slice the seared chicken and add it to the cream sauce, or pour the sauce over the pasta and place the chicken on top. Garnish with parsley and serve with bread.