A molded leadless package (MLP) semiconductor device includes a heat spreader with a single connecting projection extending from an edge of a cap of the heat spreader to a leadframe. The heat spreader can include additional projections on its edges that act as heat collectors and help to secure the spreader in the MLP. The connecting projection is attached to a lead of the leadframe so that heat gathered by the cap can be transferred through the connecting projection to the lead and to a printed circuit board to which the lead is connected. In embodiments, the heat spreader includes a central heat collector projection from the cap toward the die, preferably in the form of a solid cylinder, that enhances heat collection and transfer to the cap. The cap can include fins projecting from its top surface to facilitate radiant and convection cooling.