Preheat the oven to 500°F.
To the herb mix, add the salt, black pepper, and red pepper flakes (if using).
Take 1 1/2 teaspoons of the herb salt mix and blend with the olive oil. Toss the potatoes in this mixture, and place them in the bottom of the frying pan or roasting pan.
Place the garlic, onions, and lemons around the rim of the pan. Sprinkle these with a little bit of the herb salt mix. Set aside the pan.
Loosen the skin of the chicken, taking care not to rip the skin.
Take a 1/2 stick of the butter, mix it with a tablespoon of the herb salt mix, and blend well. Gently insert the mixture under the chicken skin. (See video.)
Gently lift the chicken and place it into the pan on top of the potatoes. Tie the chicken legs together.
Take the remaining butter and herb salt mix and melt together in a small saucepan on low heat.
Using a pastry brush, brush the skin of the chicken with the melted butter herb mix. If you do not have a pastry brush, you can spoon the melted butter herb mix over the chicken.
Transfer the pan with the chicken to the middle rack of the preheated oven.
Roast the chicken at 500°F for 10-20 minutes until the skin is golden brown. Take care not to allow the skin to burn. Once the skin is a golden brown, lower the heat to 350°F for approximately 45 minutes until the internal temperature of the chicken reaches a minimum of 165°F.
Once cooked, remove the chicken from the oven, allow it to rest for a few minutes. Afterward, slice and serve the chicken along with the potatoes, garlic, onions, and lemons.
Wrapped well, the leftovers will stay fresh in the refrigerator for 3-4 days.