To achieve that mouthwatering flaky texture of classic pie crust, you need to use the right type of fat. Butter, which is the choice of many home cooks due to its availability and familiarity, creates flaky crust because it has a higher water content than other options. As the water heats and evaporates, it makes pockets of air in the dough that become the lamination that is characteristic of a perfectly executed pastry recipe.
In contrast, lard creates flaky crust because of its high melting point. If you use ice-cold lard when you make the dough, it will take longer to melt in the oven than other types of fat. This creates pockets in the crust that lead to layering. Because it’s 100% fat, lard also creates a crispier texture.
Many crust recipes call for either all butter or all lard, but Trung Vu, a chef-instructor of Pastry and Baking Arts at the Institute of Culinary Education, prefers a 50/50 ratio. “Butter tastes great,” he said, “and although you can make pie dough with butter alone, lard will make it flakier. Lard is a neutral fat (it does not taste like pork, or almost anything, for that matter), so if you were to just use it alone, the pie dough would not be as flavorful. A 50/50 mix of both fats will give you the best of both worlds.”