1-First Step: Mise en place and seasoning the chicken Gather all ingredients and dice the chicken tenderloins into bite-sized pieces. Toss the diced chicken with 1 tablespoon olive oil, 1.5 tablespoons Italian seasoning, 1 teaspoon salt, and freshly ground black pepper so each piece is evenly coated. Preheat a large pot of salted water for the rigatoni. Having everything ready makes the cooking sequence smooth and prevents overcooking.

2-Second Step: Cook the chicken Heat an oven-safe skillet over medium heat and add 2 tablespoons olive oil. Add the seasoned chicken in a single layer and cook about 4 to 5 minutes per side, until the outside is golden and the internal temperature reaches 165°F. Remove the chicken to a plate and set aside. Leaving the fond those browned bits in the skillet adds flavor to the sauce.

3-Third Step: Build the creamy sauce Reduce the skillet heat to medium-low and melt 2 tablespoons unsalted butter. Add the diced yellow onion and sauté until translucent, about 2 to 3 minutes. Add the minced garlic and cook until fragrant, about 30 seconds to 1 minute. Pour in 3 cups whole milk, then stir in 2 teaspoons Cajun seasoning, 1 teaspoon red pepper flakes if using, and salt and pepper to taste. Add the drained 8 oz sun-dried tomatoes and 1.5 cups broccoli florets. Bring the mixture to a low simmer and cook until the broccoli softens, about 5 minutes. Keep the heat gentle to avoid curdling.

4-Fourth Step: Cook the pasta al dente While the sauce simmers, cook 10 oz rigatoni in the boiling salted water until al dente (about 1 to 2 minutes less than package directions). Reserve a cup of pasta water before draining. Drain the pasta and toss briefly with a teaspoon of olive oil to prevent sticking while you finish the sauce.

5-Fifth Step: Finish the sauce and assemble Stir 2 cups fresh baby spinach into the warm sauce until wilted. Fold the cooked rigatoni and the seared chicken back into the skillet. Add 1/3 cup prepared pesto and stir gently so the sauce coats everything evenly. If the sauce seems too thick, add a splash of reserved pasta water to loosen it.

6-Final Step: Top with cheese and broil Preheat your oven broiler. Sprinkle 1.5 cups shredded mozzarella and 1 cup shredded or grated Parmesan evenly over the pasta in the skillet. Place the skillet under the broiler for 3 to 5 minutes, watching closely, until the cheese melts and begins to brown. Let the bake rest for a few minutes before serving so the sauce sets slightly and slices hold together.