What cooking method is primarily used for a "bouilli"?

Bouilli is a cooking method that primarily involves boiling, which is why this choice is the correct one. In traditional French cuisine, bouilli refers specifically to the process of cooking food, typically meat, in a rapidly boiling liquid, often water or stock, until tender. The technique allows the flavors of the ingredients to meld while ensuring that the meat remains moist and flavorful through the boiling process.

This method also underscores the importance of temperature control and timing, as the boiling point is crucial for achieving the desired texture and flavor in various culinary applications. The other methods listed—grilling, steaming, and frying—do not align with the technique and intent behind bouilli, which is centered on the principle of boiling food to enhance its taste and tenderness.