2 boneless skinless chicken breasts (depending on size)
2 tablespoons olive oil, divided
1 pound dry linguine pasts
2 tablespoons butter
1 garlic clove, minced
3 tablespoons flour
1 and 1/2 cups milk
1/2 cup heavy cream
1/3 cup shredded Parmesan cheese
1 red bell pepper, sliced into thin strips, then strips halved
1 yellow bell pepper, sliced into thin strips, then strips halved
1/2 red onion, sliced into thin strips
2 cups sliced button mushrooms
additional Parmesan for garnish
2 and 1/2 teaspoons paprika
2 teaspoons salt
2 teaspoons garlic powder
1 and 1/4 teaspoons dried oregano
1 and 1/4 teaspoons dried thyme
1 teaspoon onion powder
1 teaspoon black pepper
1/2 teaspoon cayenne
In a small bowl, whisk together Cajun seasoning; set aside.
Heat a grill to medium-high heat. Brush chicken with 1 tablespoon olive oil and sprinkle with 2 teaspoons Cajun seasoning (about 1/2 teaspoon per side). Grill chicken until cooked through, about 8-10 minutes, rotating once halfway through. Transfer to a plate and cover with foil and allow to rest 5 minutes before slicing into thin strips.
Boil pasta in salted water according to package instructions. Reserve 1/3 cup pasta water before draining.
In a medium saucepan, melt butter over medium heat. Stir in garlic and flour and cook 1 minute, whisking constantly. While whisking, slowly pour in milk and whisk until sauce is smooth and lump free. Stir in 3 teaspoons Cajun seasoning. Bring mixture to a boil, stirring constantly, then reduce heat to low. Stir in Parmesan and cream and cook until cheese has melted. Remove from heat and set aside.
Heat remaining 1 tablespoon olive oil in a large skillet over medium-high heat. Once hot, add red and yellow peppers and red onion and saute 2 minutes. Add 1 teaspoon Cajun seasoning and mushrooms and saute 2 minutes longer.
Toss drained pasta with sauce mixture, adding reserved pasta water to thin it out as needed. Toss in pepper mixture and chicken. Serve sprinkled with parsley and Parmesan and additional Cajun seasoning as needed.