This savory roasted hen, perfect for special occasions, comes from Ben Ford, executive chef at Ford's Filling Station.
Preheat oven to 450 degrees. Fit a roasting pan with a rack; place onion and fennel slices on top of rack and set roasting pan aside.
Remove giblets from chicken and discard or reserve for another use. Rinse chicken inside and out and pat dry, very well. Season cavity with salt and pepper and truss chicken with kitchen twine.
Generously season outside of chicken and set on vegetables in roasting pan. Transfer to oven and roast until chicken reaches 165 degrees on an instant-read thermometer inserted into the thickest part of the thigh (avoiding bone), 50 to 60 minutes.
Remove chicken from roasting pan and stir thyme and butter into pan juices. Baste chicken with pan juice mixture and let stand 15 minutes.
Remove twine and place chicken breast side up. Cut through the skin between breast and thigh. Gently pull leg away to expose joint. Cut through joint to free the whole leg. Cut off wings at joints. Cut through joint where drumstick meets the thigh in a firm downward motion. Slice each breast half from bone, working knife along contour of rib cage. Serve chicken pieces with arugula salad.