Clean a cupful of large button mushrooms, canned ones may be used; cut them into bits. Put into a stewpan an ounce of butter and let it melt; add the mushrooms, a teaspoonful of salt, half a teaspoonful of pepper and half a cupful of cream or milk. Stir in a teaspoonful of flour, dissolved in a little milk or water to thicken, if needed. Boil ten minutes, and set aside until the OMELET is ready.
Make a plain OMELET the usual way, and just before doubling it, turn the mushrooms over the centre and serve hot.
The Whitehouse Cookbook, by Mrs. F.L. Gillette (Year 1887)