Preheat Oven to 450 degrees. Toss potatoes, onions and mushrooms with 2 tbls oil, half the capers (or olives) and half the spice mixture in a large bowl. Salt to your taste.
Place chicken in a rimmed, foil-lined baking sheet prepped with non-stick spray. Rub chicken with remaining two tbls oil; season with salt, fresh cracked pepper (optional to taste) and rub with remaining spice mixture (add more Herbs de Provence or Parsley if inclined).
Arrange potatoes and veggies mixture around chicken. Put remaining capers (or olives) on top of chicken and veggies.
Roast all together until potatoes are fork tender and chicken cooked through with crispy skin, about 45 minutes (check at 35 minutes).
Tip: Turn legs once during roasting stage and move veggies around for even browning.
Top with more red pepper and fresh parsley (optional) prior to serving. Pan juices are amazing, drizzle over each serving.
A recipe adapted from Bon Appetit (October, 2014), Roast Chicken w/ Potatoes & Olives.