Preheat the oven to 425 degrees F. Take the chicken out of the fridge and bring to room temperature to ensure even cooking, about 30 minutes.
Combine the butter and oil in a small bowl.
Rinse the chicken inside and out. Remove any excess fat and leftover pinfeathers from the chicken and pat the outside dry. Liberally sprinkle the inside of the chicken with the salt and pepper. Brush the outside of the chicken with the butter mixture and sprinkle with salt and pepper. Tie the legs of the chicken together with kitchen string and tuck the wing tips under the body of the chicken. Place the chicken in a roasting pan.
Roast the chicken until an instant-read thermometer inserted into the thickest part of the chicken thigh (without touching bone) reads 165 degrees F, about 1 hour. If the chicken is browning too quickly in the oven, lightly tent the chicken with aluminum foil.
Transfer the chicken to a platter and tent loosely with aluminum foil, about 20 minutes.
Slice the chicken onto a platter and serve it with the flatbreads, the Asian Cole Slaw and the Tomatillo Sauce.