Preheat your oven to 425 degrees.
In the bottom of a large baking pan, sprinkle the sliced garlic. Squeeze on the juice from one lemon & season the entire bottom of the pan with a good bit of salt & pepper.
Lay both halves of the whole chicken side by side in the middle of the baking pan, cut side down/skin side up. Season with salt & pepper. Arrange the lemon slices around the edge of the entirety of the pan. Drizzle in enough vegetable oil or olive oil to cover the bottom of the pan. Place the butter in dollops/slices all around the pan. Cover tightly with aluminum foil. For a 4 pound bird, cook for 60 minutes. For a 5 pound, cook for 75 minutes. For a 6 pound bird, cook for 90 minutes.
While the chicken is cooking, par-fry the potato spears in hot vegetable oil. Fry for a few minutes for each batch, just enough to put a light golden brown on the potatoes.
Once the time is up on the chicken, add the potato spears all around the chicken. Recover with aluminum foil and bake for another 30 minutes. Remove the foil & broil for a few minutes to put a brown on the chicken.
Serve & enjoy!