Bring a large pot of salted water to a boil. Cook the spaghetti according to package instructions until al dente. Reserve about ½ cup of the pasta water then drain the pasta.
8 oz dry spaghetti
Pat the chicken dry then season both sides with salt, black pepper, garlic powder, and Cajun seasoning. Heat olive oil in a large skillet over medium heat. Add the chicken and cook for 2-3 minutes per side, or until cooked through and golden brown. Remove from the pan and set aside.
1 chicken breast, ½ teaspoon salt, Freshly ground black pepper, ½ teaspoon garlic powder, 1 teaspoon Cajun seasoning, 1 tablespoon olive oil
In the same skillet over medium heat, melt the butter. Add the garlic and shallot and sauté for about 30 seconds until fragrant. Stir in the diced tomatoes, heavy cream, reserved pasta water, Cajun seasoning, and red chili flakes. Bring to a gentle simmer.
3 tablespoon unsalted butter, 4 cloves garlic, 1 shallot, 1 cup diced tomatoes, 1.25 cup heavy cream, ½ cup reserved pasta water, 1.5 tablespoon Cajun seasoning, ½ teaspoon red chili flakes
Add the parmesan cheese, salt, and black pepper. Stir until the cheese is melted and simmer the sauce until slightly thickened, about 2-3 minutes.
1 cup freshly grated parmesan cheese, ½ teaspoon salt, Freshly ground black pepper
Add the cooked spaghetti to the sauce and toss until evenly coated. Taste and adjust seasoning as needed.
Turn off the heat, transfer pasta to a plate, then slice the chicken and place it on top of the pasta.
Garnish with chopped parsley and extra freshly grated parmesan before serving.
2 tablespoon chopped parsley