Mixing dried porcini with tomato paste is a simple way to omit butter and still keep chicken moist while infusing it with a woodsy mushroom flavor.
Cooks' note:
Halved chicken can be roasted, skin side up, in a foil-lined shallow baking pan in upper third of a 475°F oven 30 minutes, then broiled 4 to 6 inches from heat until skin is crisp.