Preheat the oven to 415 F and line a large baking sheet with parchment paper.
Combine the olive oil, lemon juice, and dry seasonings. Set aside.
Using a large sheet pan, add the vegetables in an even layer. Add the chicken to the sheet pan and pat the thighs dry. Pour the olive oil mixture over the sheet pan and toss to coat. Add the lemon slices as well.
Transfer to the oven and roast for 40-45 minutes, tossing the vegetables halfway through. The chicken should be cooked through to 165 F and the vegetables should be tender.
Remove from the oven and allow to cool before tossing with green olives and chopped parsley.
To make the optional sauce, combine the ingredient in a container. Blend with an immersion blender until creamy. Drizzle over the chicken to serve.
Notes
All nutritional information are estimations and will vary. Estimations do not include optional ingredients.