Wipe the mushrooms free from grit with a piece of flannel, and salt; put them in a stewpan with the butter, seasoning, and ketchup; stir over the fire until the mushrooms are quite done, when pour it in the middle of mashed potatoes, browned. Then place round the potatoes slices of cold roast beef, nicely broiled, over a clear fire. In making the mushroom sauce, the ketchup may be dispensed with, if there is sufficient gravy.
Time: 1/4 hour.
Seasonable from August to October.