Step 1: Prepare and Start Pasta Water Gather all ingredients within arm’s reach. Bring a large pot of salted water to a rolling boil (6-8 minutes). Season diced chicken generously with salt, pepper, and ½ teaspoon Italian seasoning.

Step 2: Sear the Chicken Heat 2 tablespoons olive oil in a large 12-inch skillet over medium-high heat. Once shimmering, add seasoned chicken in a single layer. Let sit undisturbed for 3-4 minutes to develop a golden-brown crust. Stir and cook an additional 2-3 minutes until internal temperature reaches 165°F (74°C). Remove to a clean plate, preserving all browned bits in the skillet.

Step 3: Build the Aromatic Foundation Reduce heat to medium. Add 1 tablespoon butter to the skillet. Sauté diced onion for 1-2 minutes until translucent. Add minced garlic and cook 30-45 seconds until fragrant. Add sun-dried tomatoes and red pepper flakes. Stir constantly for 1 minute to bloom spices.

Step 4: Deglaze and Build Sauce Base Pour chicken broth into the skillet, using a wooden spoon to scrape up all caramelized browned bits from the bottom. Simmer for 1-2 minutes. Reduce heat to medium-low. Slowly whisk in heavy cream, pouring gradually over 20-30 seconds while whisking continuously.

Step 5: Incorporate Parmesan Cheese Simmer gently for 2-3 minutes without boiling. Remove from direct heat or reduce to low. Gradually add freshly grated Parmesan cheese in three additions, whisking thoroughly between each addition. The sauce should be glossy and smooth. Taste and adjust salt and pepper as needed. Add fresh lemon juice.

Step 6: Combine Pasta, Chicken, and Sauce Add drained al dente pasta and seared chicken back into the skillet. Toss gently but thoroughly until all pasta is coated. Reserve 1 cup pasta water before draining. If the sauce feels too thick, add pasta water 1 tablespoon at a time until desired consistency is reached.

Step 7: Finish and Serve Transfer to warmed shallow pasta bowls. Garnish generously with fresh basil leaves and additional freshly grated Parmesan cheese. Serve immediately while the sauce remains silky and hot.