Preheat the oven to 425-degrees F. Coat a sheet pan with cooking spray.
In a large bowl, whisk together the olive oil, lemon juice, rosemary, garlic, salt, and pepper.
Add the chicken, potatoes, carrots, and parsnips to the dressing and coat to toss.
Gently pour the vegetables and chicken onto the prepared baking sheet, making sure they are in a single layer. Top with the lemon slices. Place in the oven and roast for 40 to 45 minutes until the chicken reaches a minimum internal cooking temperature of 165-degrees F.
Into each of 4 containers, scoop about 2 cups of chicken and vegetables.
Storage: Place airtight containers in the refrigerator for up to 1 week. To freeze, place freezer-safe containers in the freezer for up to 2 months. To defrost, refrigerate overnight. To reheat individual portions, microwave uncovered on high for 2 to 2-1/2 minutes.
Recipe copyright Toby Amidor, Smart Meal Prep for Beginners, Rockridge Press, 2018. Photo courtesy of Elysa Weitala