Strutto is lard, rendered pork fat, that has been used by women for centuries for frying and making pastry. It gives an incomparable crispness to fried food and an unbeatable flaky texture to pastry doughs. As a cooking fat, its contribution to both taste and texture cannot be duplicated. The purest lard is called leaf lard; pork back fat is the second choice. Ask your butcher for help in finding it. To render it, cut the pork fat into small pieces, put it in a deep, heavy-bottomed saucepan, cover with a small amount water, and set it over low heat. Let it cook until it has become a transparent liquid. Skim off the pork cracklings—they are delicious by themselves or you can bake them into bread—pour the lard into a ceramic container, and let it sit at room temperature until it cools and solidifies into a creamy white substance. Keep it in the refrigerator or freezer. If you opt for a commercial lard, taste it carefully. Lard should have no taste and no odor. Many traditional grandmothers insist on using lard, but fear of cholesterol and calories has scared many cooks, even nonne. Some nonne substitute margarine. Ironically, lard actually has less cholesterol than butter.