Step 1

Place a rack in the middle of the oven and preheat it to 450ºF. Place the potatoes, onion, olive oil, and water in a large skillet. Season all over with salt. Crack pepper over top to taste. Toss to combine.

Step 2

In a medium bowl, stir together the mayonnaise and the mustard. Add the chicken thighs and toss to coat on all sides. Season all over with salt and pepper. Nestle the thighs on top of/in between the potatoes. Crack more pepper over top if you wish.

Step 3

Transfer pan to the oven uncovered and cook for 45 minutes or until evenly golden, checking after 30 minutes to ensure everything is browning evenly — if the onions are getting too dark, add a few more tablespoons of water to the pan.

Step 4

Sprinkle tarragon or herb of choice all over the roasted chicken and potatoes. Transfer chicken to a platter. Toss potatoes with herbs and remaining juices in the pan. Taste. Adjust with more salt or pepper if necessary. Spoon potatoes around chicken on the platter. Serve.