Preheat the oven to 425°F. Add a large rimmed baking sheet to the oven on the middle rack to warm up as the oven preheats.

Prepare the garlic, chicken, and potatoes: Remove any loose outer papery leaves from the garlic and slice ¼ to ½-inch off the top of the cloves. Place the garlic in the center of a piece of foil large enough to cover the entire head once wrapped. Drizzle the cut side with 1 tablespoon of oil, then pull up the sides of the foil to close. Place on the baking sheet in the preheating oven. Add the remaining 3 tablespoons of the oil and the ranch seasoning to a large bowl and stir to combine. Pat the chicken dry, then add it to the bowl with the potatoes and toss to coat.

Roast: Carefully remove the preheated pan from the oven and place the chicken, skin-side down, on the baking sheet, surrounding it with a single layer of potatoes. Bake until golden brown on the bottom, 15 to 20 minutes. Flip the chicken and stir the potatoes, then return the pan to the oven and bake until the chicken reaches an internal temperature of at least 165°F and the potatoes are tender, 10 to 15 more minutes.

Serve: Remove the garlic from the pan and carefully unwrap. Squeeze lemon juice over the chicken and potatoes and garnish with the parsley. Serve with the roasted garlic, squeezing the roasted cloves out of their skins and scattering them over the chicken and potatoes. Store leftovers in an airtight container in the fridge and enjoy within 3 days. Love the recipe? Leave us stars and a comment below!