Peas may be substituted for the sweetbreads

Cook one slice of onion in two tablespoons of butter for five minutes, taking great care not to brown.
Chop one cup of mushrooms very fine and a cup of cooked sweetbreads, also chopped very fine. Put this into the onion and butter. Add one-fourth cup of fine bread crumbs; one-half cup of green sweet pepper, chopped fine, half teaspoon of salt, yolks of two eggs, well beaten.
All this to be well beaten together.
Add one cup of thick white cream sauce. Lastly, fold in the stiffly beaten whites of two eggs. Butter the timbale molds thoroughly. Set them in pan of hot water. Cover with buttered paper and bake fifteen minutes.
Remove from molds and serve with any desired sauce. Peas may be substituted for the sweetbreads if a strictly Lenten menu is desired.