Butter is an essential ingredient in baking and comes in various forms. When making flaky pastries, cold butter is crucial. Smushing it between your fingertips helps incorporate it into the dough and control its consistency. Cold butter forms layers, giving shape and flavor to pastries like croissants. Chop the butter into cubes, smush it into the flour mixture, and follow the recipe. This technique is particularly important for laminated pastries. Creaming butter is not suitable for flaky pastries as warm butter may melt and create greasy results. Adding rum or cold water brings the dough together, and the butter chunks will melt in the oven, adding tenderness and layers.