Internal combustion engine pistons are provided with aluminum bodies with highly insulative ceramic inserts cast in place in the upper combustion chamber defining wall. In each of the disclosed embodiments, the ceramic insert has tapered edges to dovetail the insert in place. A fibrous ceramic cushioning layer applied around the insert edge before casting distributes cooling stresses and allows limited relative expansion and contraction of the aluminum body and ceramic insert without overstressing either of the members. Other features are also included.