When it carefully. Warm the milk and butter in the one container. On gradually boil Pour the mixture of milk and butter into the mashed potatoes. Stir well . Or beat to combine.
When it's warm milk and butter, and details in one container. When it boils pour milk mixture gradually, , and butter into the mashed potato. The or hit together
When it was fine, and then warm the milk and butter in another container when boiling slowly, pour the mixture into the milk and butter in it's grinding, or beat them together.