Vapor condensers and cooling apparatuses to facilitate vapor condensation cooling of a coolant employed in cooling an electronic device or electronic subsystem. The vapor condenser includes a thermally conductive base structure having an operational orientation when the condenser is facilitating vapor condensate formation, and a plurality of thermally conductive condenser fins extending from the thermally conductive base structure. The plurality of thermally conductive condenser fins have a varying cross-sectional perimeter along at least a portion of their length. The cross-sectional perimeters of the plurality of thermally conductive condenser fins are configured to increase in a direction of condensate travel.