This method for producing a packaged food product portion includes the following steps: providing a cup defining an inner area for receiving the food product; cold pouring, at a temperature below 50° C., the food product into the receiving area of the cup; covering the food product using a thermally insulating lid arranged such that thermally conducting flaps of the cup extend toward the outside of the lid after the covering step; folding the flaps on an outer face of the lid opposite the receiving area; and heat-sealing the flaps on the outer face.