French Onion Soup
["4 large white onions", "2 large yellow onions", "1 tsp. dry mustard", "1 tsp. salt", "1 tsp. pepper", "1/4 c. butter", "4 c. beef stock", "4 c. chicken or poultry broth", "1 loaf French bread", "Parmesan cheese", "Gruyere cheese", "1 bottle dry sherry"]
["Slice onions paper thin.", "Fill large pot to the top with onions.", "Add 1/4 cup of butter and simmer on low until onions are translucent.", "Mix in 1 teaspoon of dry mustard, salt and pepper. Add equal amounts of beef and chicken stock and 1/4 cup of sherry. Cook on low (without boiling) for 6 to 8 hours a day, for two days. Add sherry to replace fluid as it evaporates.", "Cut French bread into thin slices and place on a baking sheet.", "Bake in oven on low temperature for 3 to 4 hours, until hard.", "Grate Gruyere cheese on bread and continue baking for 1 hour."]
["white onions", "yellow onions", "dry mustard", "salt", "pepper", "butter", "beef stock", "chicken", "bread", "Parmesan cheese", "Gruyere cheese", "sherry"]