Preheat the oven to 425°F (220°C). Line a large baking sheet with foil and set a wire rack on top.
Place the whole chicken breast-side down on a cutting board. Using kitchen scissors or a sharp knife, cut along both sides of the backbone to remove it.
Flip the chicken breast-side up and press firmly on the breastbone to flatten the chicken into a spatchcock shape.
In a small bowl, combine the olive oil, salt, black pepper, minced thyme, minced garlic, lemon zest, and lemon juice.
Rub the lemon-garlic mixture all over the chicken, working some under the skin where possible and spreading the rest on the exterior.
Place the prepared chicken on the wire rack breast-side up and roast in the preheated oven for about 45 minutes, or until an instant-read 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.