Mirepoix becomes a Matignon when which of the following is added?

Mirepoix is a foundational element in many French dishes, traditionally consisting of diced onions, carrots, and celery, used to build flavor in stocks, soups, and sauces. When a fat source is added to the mirepoix—typically in the form of butter, oil, or another type of fat—it transforms into a Matignon. This process allows the flavors of the mirepoix to be released and enhanced while also introducing richness and depth to the dish.

The fat helps to sauté the vegetables, ensuring they soften and begin to caramelize, which adds a more complex flavor profile. A Matignon may also include the addition of ham or lardons, further enriching the dish, but the key transformation occurs with the introduction of fat, differentiating it from a standard mirepoix.

Understanding this is crucial because it highlights the importance of technique in French cuisine, where the precise combination and treatment of ingredients define the outcome of a dish.