Preheat oven to 400℉.In a medium sized bowl or glass measuring cup whisk together first seven ingredients. Set aside.
Add chicken thighs to a large roasting pan with an even distance between thighs. Wash and pierce potatoes. Add to roasting pan arranging around thighs. Pour rosemary lemon oil mixture over top of chicken and potatoes making sure all surfaces are covered. Bake uncovered for 20 mins.
Meanwhile, using a damp paper towel to clean off mushrooms of any dirt.
Once 20 mins has elapsed lower temperature of oven to 375℉ and removed roasting pan from oven. Evenly distribute mushrooms in roasting pan and continue baking uncovered until chicken is cooked through (165℉ internal temperature) and potatoes are tender, about 40 mins more. 15 mins before roasting time is done remove pan from oven and spoon juices over top of mushrooms. Roasting time will take longer if there is little room between chicken and potatoes. Keep a watchful eye on chicken and potaotes after time has elapsed on the second bake.
Garnish with lemon wedges from reserved lemon (optional).
*Please use as many organic ingredients as possible. Cooking Tips
For extra flavor add an additional 1/2 tbsp of dried ground rosemary and 2-3 more garlic cloves.