A plastic table structure includes a tabletop comprising a thin polymer shell layer surrounding an expanded foam core. The multiple layers of the finished tabletop are molded concurrently in a one-pass biaxial or centrifugal rotational molding process, and cured in an oven. The method includes the steps of introducing polymeric material into a mold, and rotating the mold while heating it to a first temperature so as to form a molten shell of a portion of the polymeric material on the inside of the mold. A foaming agent is introduced within the mold and mixes with a second unmelted portion of the polymeric material and distributes throughout the mold. When the mold reaches a second higher decomposition temperature, the foaming agent causes expansion of the second portion of the polymeric material, forming an expanded foam core inside the shell.