Grease a wire rack and place it in a large baking dish or roasting pan. Preheat the oven to 375°F (190°C).
Turn the chicken onto its breast on a cutting board. Using poultry or kitchen scissors or a sharp filleting or chef’s knife, cut down both sides of the backbone to remove it (discard the backbone or save it & add it homemade broth). Turn the chicken breast side up. Turn the legs in & tuck the wings behind the chicken (see pic of whole roasted chicken). Carefully run your fingers underneath the skin of the chicken loosening it from the flesh over the breast & legs - this is where you’re going to spread the butter mixture.
Combine butter, parsley, rosemary, thyme, garlic, salt & pepper in a small bowl using a fork to mash it all together.
Spread the butter mixture evenly between the skin and the flesh of the chicken across the breast & legs of chicken.
Place the chicken, breast side up, on the prepared rack. Roast, uncovered, in the preheated oven for about 1 1/4 hours or until the chicken is cooked and the juices run clear when chicken is pierced around the thigh bone or a meat thermometer reads 165°F (74°C) when inserted into the thickest part of the thigh. Cover loosely with foil & let stand for 5 minutes to allow juices to settle. Chop or carve the chicken to serve. I generally remove the legs & the breast from the ribs, then the wings. It will serve 6 people (as per nutrition guidelines) but I think 3 to 4 generous portions is more realistic.
If you're feeling so inclined, reserve the pan juices, add a splash of sherry & reduce the mixture to give you a spoonfuls of buttery pan drippings to serve with the chicken.