In a large bowl, mix together the grated Emmenthaler and Gruyere cheeses; set aside.
In a large soup pot over medium-high heat, heat the butter and corn oil until hot but not smoking. Add the sliced onions and saute, stirring frequently, for 10 to 12 minutes until they are nicely browned. When the onions are browned, add the chicken stock and garlic. Bring to a boil and cook, uncovered, at a gentle boil for 20 minutes. Remove from heat.
Using a food mill, push the soup mixture through it into a large bowl or pan. Add salt and pepper to taste.
At this point, the soup can be cooled to room temperature and refrigerated in an airtight container up to 2 days. To use, return to simmer before finishing soup with bread and cheese.
Preheat oven to 400 degrees F.
Arrange the baguette bread slices in one layer on a cookie sheet. Place in oven and bake, without turning, for approximately 8 to 10 minutes or until they are well-browned on both sides. Remove from oven.
Place 6 to 8 prepared bread slices in each onion soup bowl. Arrange the bowls on a large cookie sheet.
Turn the oven temperature up to 425 degrees F.
Sprinkle approximately 2 tablespoons of the combined grated cheeses on top of the bread slices in each bowl. Add the prepared onion soup by filling the bowls to the rim (if you need a little more liquid, add a little water to the soup in each of the bowls).
Sprinkle 1/2 cup of grated cheeses on top of the onion soup in each bowl, making sure that it not only covers the soup, but also touches the entire inside edge of each bowl, so that it will adhere to the edge as it melts during cooking.
Tip: For an onion soup not to collapse, the soup bowl has to be filled to the rim with the onion soup and the bread. The cheese layer should cover the whole surface, so it will stick to the sides and form a crust that holds its shape and doesn't sink.
Set the cookie sheet containing the bowls of soup in the oven and cook for 30 minutes until the cheese is melted and browned. Remove from oven and serve immediately. If the top is not well browned after 30 minutes, place the bowls under the hot broiler of your oven for a few seconds before serving.
Makes 6 servings.
* Learn how easy it is to make your own homemade Chicken Stock - Basic Chicken Stock.
French Onion Soup Recipe - Onion Gratinee Soup: https://whatscookingamerica.net/lindasandberg/soups/onionsoup.htm