Sometimes the urge to bake strikes without warning, leaving your eggs and butter unprepared for the sudden call to action. Fortunately, there's no need to wait long if you need room-temperature eggs or softened butter for a recipe. Cold eggs can be warmed in minutes by putting them in a bowl of very warm water. To soften cold butter quickly, you need to increase the surface area that's exposed to room temperature. Cut the butter into small cubes, separate the cubes into a single layer, and let them sit on the counter. They'll reach optimal creaming temperature (65° to 68°F) in about 30 minutes. I've found that flattening butter with a rolling pin or skillet, as some sources suggest, doesn't offer a significant time advantage over the cubing method.
