Phospholipase C (PLC) enzymes play a pivotal role in the degumming process of edible oils, which is essential for producing high-quality refined oils. The enzymatic degumming process, compared with conventional chemical methods, offers significant advantages including improved oil yield, reduced environmental impact, and lower operational costs. However, the industrial application of PLC enzymes is often hindered by their limited stability under harsh processing conditions. This has driven extensive research efforts toward engineering thermostable PLC variants that can withstand the high temperatures and harsh environments typical of oil refining processes. In this review, we explore the latest advancements in the application, design and optimization of thermostable PLC enzymes. We discuss the fundamental economic and ecological interest behind the goal of obtaining thermostable enzymes, and two approaches to the problem, namely the search for enzymes in thermophilic organisms and the design of new sequences with improved stability and activity parameters.