Prep the chicken: Pat chicken dry and slice into thin strips or small bites. Toss with 2 tablespoons Cajun seasoning, 1/2 teaspoon salt, and a drizzle of olive oil until evenly coated.

Boil the pasta: Bring a large pot of salted water to a boil. Cook pasta to al dente per package directions. Reserve 1 cup of pasta water, then drain.

Sear the chicken: Heat 1 tablespoon olive oil and 1 tablespoon butter in a large skillet over medium-high. Add chicken in a single layer. Cook 4–6 minutes, turning once, until browned and cooked through. Transfer to a plate and tent with foil.

Optional veggies: In the same pan, add a touch more oil if needed. Sauté sliced bell pepper and onion with a pinch of salt for 3–4 minutes until slightly softened and charred at the edges. Remove and set aside with the chicken.

Start the sauce: Lower heat to medium. Add 2 tablespoons butter to the pan. Stir in minced garlic and cook 30–45 seconds until fragrant—don’t let it brown.

Creamy base: Pour in heavy cream and bring to a gentle simmer. Stir and scrape the browned bits from the pan to enrich the sauce.

Add the cheese: Reduce heat to low. Gradually whisk in Parmesan in small handfuls until melted and smooth. If it looks too thick, add a splash of chicken broth or reserved pasta water.

Season the sauce: Add 1–2 teaspoons Cajun seasoning (to taste), a small pinch of salt, and a few grinds of black pepper. Stir in a teaspoon of lemon zest for brightness.

Toss it all together: Add the drained pasta, chicken, and any sautéed veggies to the sauce. Toss gently until every piece is coated. If the sauce tightens, loosen with more pasta water, a few tablespoons at a time, until glossy and silky.

Finish and serve: Taste and adjust seasoning. Top with chopped parsley, extra Parmesan, and red pepper flakes if you want more heat. Serve in bowls with lemon wedges on the side.