Fill a large pot with water and bring to a gentle boil—you want steam rising steadily, not a rolling angry boil. Place chicken breasts in the water and reduce heat to medium-low. Poaching at this lower temperature keeps the chicken from tightening up and squeezing out all its moisture, which is why most recipes end up with dry chicken. Let it cook for 25-28 minutes until a meat thermometer reads 165°F at the thickest part.

While the chicken poaches, get your pasta water ready in a separate pot. Salt the water generously (it should taste like the ocean, Marco always says). Bring to a rolling boil, then add the whole wheat rotini and cook for 8-10 minutes until the pasta is just tender but still has a slight bite when you chew it. Overcooked pasta becomes mushy and loses its texture in the finished dish.

Reserve 1/2 cup of pasta water before draining—this becomes your secret weapon for loosening the dressing later. Drain the pasta and immediately transfer it to a large mixing bowl while still hot. Here's where the magic happens: whisk together the olive oil, lemon juice, Dijon mustard, sea salt, and black pepper, then pour this dressing over the warm pasta right now while it's still steaming. The warm pasta absorbs every drop of flavor instead of repelling it like cold pasta would.

Remove the poached chicken from the water and let it cool on a cutting board for about 5 minutes. Dice it into bite-sized pieces (roughly 3/4-inch chunks work best). I know the temptation is to shred it, but chunks hold their shape better throughout the week and make this beautiful chicken pasta salad summer recipe feel more intentional on the plate.

Add the diced chicken to the warm, dressed pasta and gently fold everything together. Now fold in the mozzarella cheese, cherry tomatoes, cucumber, red onion, and Kalamata olives—save the fresh basil for last because you want it bright and intact, not bruised. This is your last chance to taste and adjust seasonings; add more salt or lemon juice if needed.

Gently fold in the fresh basil leaves and let the entire beautiful filling cool to room temperature (about 15-20 minutes). If you're serving immediately, this is fine. If you're making it ahead—which I recommend—refrigerate it for at least 2 hours and up to 3 days. The flavors actually deepen as everything sits together.