For the brined chicken: Bring 1 1/4 gallons of water to a rolling boil. Remove from the heat and add the salt, oregano, rosemary, thyme, garlic, pepper, juniper berries and bay leaves. Stir until the salt is completely dissolved.
Transfer the brine to a lidded container and refrigerate until completely cool, about 1 1/2 hours.
Place the chicken in the brine breast-side down and weigh it down with a heavy plate or a bowl filled with water so it's completely submerged in the brine. Cover and transfer to the refrigerator to brine for 12 hours.
For the herbes-de-Provence baste: In a medium bowl, put the olive oil, butter, canola oil, lemon juice, vinegar, herbes de Provence, onion, oregano, rosemary, sugar, pepper, chile flakes, lavender and salt. Whisk together until the butter and oil are fully blended.
Roast the chicken: Preheat the oven to 375 degrees F. Remove the chicken from the brine and pat dry inside and out with paper towels.
In a 13-by-9-inch roasting pan, shingle the potatoes starting from the corner of the pan. Continue shingling until the bottom of the pan is covered in 2 to 3 layers of potatoes.
Brush the chicken inside and out with half of the baste; reserve the other half for later. Cross the legs of the chicken and tuck them into the tail. Place the chicken breast-side up in the roasting pan and transfer to the oven.
Roast for approximately 60 minutes, brushing the chicken with the reserved baste every 6 to 8 minutes. When done, both the chicken and potatoes should be golden brown and a meat thermometer inserted into the thickest part of the chicken should read 155 to 160 degrees F.
Transfer the chicken to carving board, cover loosely with foil and let rest for 10 to 15 minutes.
Carve the chicken into quarters and serve with the roasted potatoes.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.