Bring a large pot of salted water to a boil and cook the linguine following the package instructions, reserving half a cup of the pasta water before draining. Heat the olive oil in a wide skillet over medium-high heat and season the chicken with salt and pepper; cook for about 5 to 7 minutes until golden and fully cooked, then transfer it to a plate. In the same skillet, melt the butter and add minced garlic, paprika, and red pepper flakes if using, cooking for around one minute until aromatic but not browned. Stir in Dijon mustard, lemon juice, lemon zest, and chicken broth or reserved pasta water, scraping the skillet to lift any browned bits, and let it simmer gently. Pour in the heavy cream and half of the chopped parsley, stirring gently and cooking until the sauce slightly thickens, about 2 minutes. Return the chicken to the pan along with the drained linguine and parmesan cheese, tossing thoroughly to combine, adding reserved pasta water as needed for desired sauce consistency. Taste and season with additional salt and black pepper as necessary, then sprinkle with the remaining parsley and extra parmesan before serving immediately to enjoy all the vibrant flavors.