The best way to prepare Spatchcock Chicken - a flattened chicken is rubbed with garlic herb butter and roasted on a sheet pan until gorgeously browned, surrounded by tender vegetables. It's a humble meal with impressively flavorful results!
Preheat oven to 425 degrees. Spray an 18 by 13 inch baking sheet with non-stick cooking spray or line with parchment paper.
To prepare chicken turn the chicken breast side down on a cutting board. Cut spine from chicken using heavy duty kitchen shears, trim down both sides of the backbone from end to end to remove completely (reserve in fridge for chicken stock if desired).
Optionally for ease in flattening chicken in the next step you can make a small cut down the upper center of it (the sternum) before turning the chicken. Trim excess visible fat from the chicken, season inside the chicken with salt and pepper.
Turn chicken to opposite side, use the heel of your hand forcefully press between the center of the chicken breasts to crack the breastbone and flatten the chicken (if needed use a second hand over first for added pressure).
In a mixing bowl using a spatula stir together butter, 1 1/2 tsp each garlic, thyme, rosemary and the lemon zest. Season with salt and pepper to taste (I use about 3/4 tsp salt and 1/4 tsp pepper).
Using the back of a spatula or your finger separate the skin from the chicken to create a pocket for the butter (start at the neck and run down near the opposite end but not all the way through or butter will melt out). Also do this for the thighs. Dab outer chicken skin dry with paper towels.
Spread the butter mixture under the chicken skin breasts and thighs (it helps to add about a spoonful then spread over the the top of the chicken skin to move it downward).
Transfer the chicken to prepared baking sheet breast side up, turn and tuck the wings tips under the chicken. Season the chicken evenly with paprika, salt and pepper to taste.
In a large mixing bowl toss together potatoes, carrots, remaining garlic, rosemary thyme, and olive oil while seasoning with salt and pepper to taste.
Spread vegetables around chicken (you can use space under neck area and under wingtips if needed).
Roast in oven until chicken breasts are 160 to 165 in center on an instant read food thermometer (thighs should be at least 165 degrees, but it's okay if thighs are hotter. The chicken breasts you don't want past that temperature or they'll dry out), about 50 to 60 minutes. If needed you can toss the vegetables around 30 minutes if they are beginning to brown.
Tent with foil and let chicken rest 10 minutes before carving (for juicier chicken). Garnish everything with parsley and serve with lemon wedges for spritzing over chicken and vegetables.
Notes
I don't recommend using small thin carrots here, the larger will work better as they won't over-cook by the time the chicken is baked through.