Preheat oven to 425 degrees or fire up the grill.
Mix together first seven ingredients.
Add oil to the mixture until generously coated.
Add chicken to sheet pan and surround it with vegetables.
Cook for roughly 15 minutes.
While the chicken and veggies are cooking, toss leeks with lemon zest and add oil as needed.
Remove chicken and veggies from the oven and add the leeks to the top and cook for another 20 – 25 minutes.
While the chicken, veggies, and leeks finish cooking, combine Greek yogurt, garlic, and dill in a small bowl.
When chicken is done, top with arugula, Greek Yogurt, and optional garnishes.
Enjoy!