Fat, and especially butter, plays a crucial role in patisserie because it directly influences both texture and flavor of cakes, cookies, brownies and other sweet baked goods. It creates tenderness by coating flour particles and limiting gluten development, which helps produce delicate, melt-in-the-mouth products rather than tough ones. In laminated pastries like croissants or puff pastry, butter is essential for creating layers, as it separates thin sheets of dough and produces the light, flaky structure during baking. Beyond texture, butter also contributes to richness and enhances flavor, giving patisserie its characteristic indulgent taste. It can also trap air when creamed with sugar, helping to provide structure and volume in cakes and other baked goods.