Preheat the oven to 425°F (220°C). Line a large baking sheet with foil and set a wire rack on top.
Place the chicken breast-side down on a cutting board. Using kitchen scissors or a sharp knife, cut along both sides of the backbone and remove it.
Flip the chicken breast-side up and press firmly on the breastbone to flatten the bird (spatchcock).
In a small bowl, combine the olive oil, salt, black pepper, minced thyme, minced garlic, lemon zest, and lemon juice.
Rub the mixture all over the chicken, including under the skin where possible and over the exterior.
Place the chicken breast-side up on the prepared rack and roast for about 45 minutes, or until a meat thermometer inserted into the thickest part of the thigh reads 165°F (74°C) and the skin is golden and crispy.
Remove the chicken from the oven and let it rest for 10 minutes before carving and serving warm.