the.com/slow roast

means To cook something at a low temperature for an extended time so tough tissue breaks down slowly into tenderness — or, by extension, to criticize someone gradually and relentlessly rather than with one sharp insult.

from A straightforward compound of 'slow' and 'roast,' describing a cooking method that predates the phrase itself — meats and roots cooked over low, lingering heat for hours. The culinary sense is old practical knowledge, formalized as a named technique once ovens could hold steady low temperatures. The figurative sense — a prolonged, drawn-out mocking or shaming of someone, as opposed to a quick 'roast' in the comedic sense — is a more modern extension, borrowing the kitchen's patience for a slower kind of social burn.