Start by shredding or chopping your rotisserie chicken into bite-sized pieces if not already done. Dice the red onion and celery into uniform 1/4-inch pieces—this ensures even texture throughout the salad and helps them distribute evenly when mixed. Roughly chop the baby spinach to break up any large clumps. Measure out your mayonnaise and Greek yogurt, and have your salt and freshly ground black pepper ready. I find that doing all your prep work first makes the final assembly quick and ensures nothing gets missed.

In a large bowl, whisk together the mayonnaise and Greek yogurt until well combined and smooth. The Greek yogurt adds a light creaminess while keeping the salad from becoming too heavy. Season this mixture with salt and freshly ground black pepper, stirring to incorporate evenly. This creates a flavorful base that will coat everything when you add the remaining ingredients.

Add the shredded chicken, diced red onion, diced celery, and baby spinach to the creamy base from Step 2. Gently fold everything together using a spatula or wooden spoon until all ingredients are evenly coated with the dressing. I like to taste as I go and adjust the seasoning if needed—sometimes the chicken absorbs more salt than expected, so a pinch more might be welcome. Serve immediately or refrigerate until ready to enjoy.