A rolling pin is a kitchen tool used to flatten and spread out dough. It's usually a smooth cylinder made of wood, marble, or plastic, with handles on both ends (or sometimes no handles at all). When you press down and roll it back and forth across a ball of dough, it spreads the dough into a thin, flat sheet perfect for making pie crusts, cookies, pasta, or pizza.

Using a rolling pin takes a bit of technique. You need to apply steady, even pressure and work from the center outward, rotating the dough occasionally so it doesn't stick to the counter. Bakers often sprinkle flour on both the counter and the rolling pin to keep everything from getting too sticky.

Before rolling pins were invented, people flattened dough with their hands or used smooth bottles or wooden cylinders. The French style of rolling pin, which is a tapered wooden rod without handles, gives bakers more control and feel for the dough. Some rolling pins are hollow inside and can be filled with cold water or ice, which helps keep butter-based doughs cold while you work with them, making flakier pie crusts.