Mary'S Onion Casserole
["8 large yellow onions, sliced thin", "3 Tbsp. butter", "salt and pepper"]
["Put a layer of sliced onions in bottom of a casserole serving 4 people.", "Sprinkle with salt and pepper.", "Add 8 small nobs of butter around each layer of onions.", "Repeat until casserole is full.", "Cover and bake 1 hour at 350\u00b0 without removing cover."]
["yellow onions", "butter", "salt"]