A heating element assembly in the form of a heating shelf and a method of manufacturing heating shelf assemblies. The heating shelf may be used in display cabinets to heat ready made foods such as cookies, muffins, donuts, pizza, sandwiches and the like. The preferred heating shelf includes thermochromic materials, or an LED indicator, which provide a visual indica of shelf temperature. The preferred heating shelf provides intimate contact with the heated food products, thus optimizing heat transfer between the heating shelf and the food products. Optionally provided, varied surface watt density in the heating shelf allows for accurate heat placement such that the food products can be evenly warmed while avoiding over warming. In another embodiment, the heating shelf includes two resistance heating elements. The first heating element is a temperature booster used for defrosting and heating, while the second heating element is a maintenance heater to maintain heated food at a serving temperature.