What cooking technique involves immersing food in boiling water for a short period, then rapidly cooling it?

The technique of immersing food in boiling water for a short period followed by a rapid cooling process is known as blanching. This method is primarily used to halt enzyme actions which can cause loss of flavor, color, and texture. Blanching is often employed for vegetables to preserve their bright colors and nutrients before freezing or further cooking. The brief exposure to boiling water cooks the food just enough to set its color and soften it slightly, while the rapid cooling in ice water stops the cooking process almost immediately, maintaining the desired texture and preventing overcooking.

Other techniques mentioned, such as poaching, involve gently cooking food in water or stock at lower temperatures, simmering refers to cooking food in liquid at just below boiling point, and sautéing entails cooking food quickly in a small amount of oil or fat over relatively high heat. Each of these techniques serves different purposes and results in varying textures and flavors in the final dish.