01 - Bring a large pot of generously salted water to a rolling boil. Add the pasta and cook according to package directions until al dente. Drain thoroughly, rinse under cold running water to halt cooking, and set aside to cool completely.
02 - Pat the chicken breasts dry and season both sides evenly with garlic powder, salt, and freshly cracked black pepper. Heat olive oil in a large skillet over medium heat until shimmering. Sear the chicken for 6–7 minutes per side until deeply golden and cooked through to an internal temperature of 165°F. Transfer to a cutting board and rest for 5 minutes before slicing into bite-sized cubes.
03 - In a mixing bowl, combine the mayonnaise, Dijon mustard, honey, apple cider vinegar, and olive oil. Whisk vigorously until the dressing is smooth and emulsified. Season with salt and pepper to taste, adjusting the balance of sweetness and acidity as desired.
04 - In a large serving bowl, combine the cooled pasta, sliced chicken, halved cherry tomatoes, diced cucumber, diced red bell pepper, thinly sliced red onion, and baby spinach. Pour the honey mustard dressing over the top and toss gently until every component is evenly coated.
05 - Plate immediately and garnish with fresh herbs if desired. For the best flavor development, refrigerate for at least 1 hour before serving. This salad holds well chilled for picnics, potlucks, or a satisfying light dinner.