Here is the one I use- also Julia Child but a little different version
JULIA’S FRENCH ONION SOUP
Plain Brown Beef Stock for about 2 quarts from Julia Child & More Company
2 or more quarts sawed beef bones, including knuckles and some meaty scaps attached; plus veal and poultry bones, raw and/or cooked (my note: I use beef, chicken and pork)
2 large carrots, scrubbed and roughly sliced
3 large onions, peeled and roughly chopped
sufficient water to cover all ingredients
1 large leek, washed (optional)
3 celery ribs with leaves, washed
1 tb coarse or kosher salt (or table salt)
1 large herb bouquet tied in washed cheesecloth (8 parsley sprigs, 1 large imported bay leaf, 1 tsp dried thyme, 4 whole cloves or allspice berries, 3 large cloves garlic, unpeeled)
Spread the bones and meat scraps (except for poultry) and the carrots and onions in a roomy enough roasting pan; set in the upper middle level of a 450 degree oven and roast for 40 or more minutes, turning and basting ingredients several times with accumulated fat until nicely browned (my note: I usually use some chicken thighs on the bone and I do put them in the roasting pan right away with the other meats/bones). Transfer to a large soup kettle, leaving fat in pan. Discard fat and de-glaze pan- pour in a cup or so of water and set over heat, scraping coagulated roasting juices into the liquid. Pour into the kettle, and add enough cold water to cover ingredients by 2 inches (my note: sometimes I will use some canned broth along with the water here but if you do this, use low-sodium beef or chicken broth). Bring to the simmer, skim off gray scum that will rise to the surface for several minutes, then add rest of ingredients. Cover partially and simmer slowly 4-5 hours at least, adding more water if needed to cover ingredients. Strain into a large bowl, chill, peel coagulated fat off surface, and your stock is finished. If your stock lacks savor, boil it down in a large kettle after degreasing to concentrate it.
For the onion soup:
3 tb butter
1 tb olive oil
6 cups thinly sliced yellow onions (about 1-1/2 lb)
½ tsp sugar
1 tsp salt
2 tb flour
2 quarts homemade stock
2 cups dry white wine or dry white French vermouth
salt & pepper
Melt the butter with the oil in a 4-qt pan. Stir in the sliced onions. Cover and cook slowly for 20 minutes, stirring up occasionally, until onions are tender and translucent. Raise heat to moderately high, stir in the sugar and salt, and cook 20-30 minutes more, stirring frequently until onions have turned a fine, deep caramel brown. Lower heat to moderate, blend in the flour, and cook, stirring, for 2-3 minutes. Remove from heat and blend in 2 ladlefuls hot stock. Stir in the rest and the wine. Season lightly to taste, bring to the boil then simmer slowly, partially covered, for 30 minutes. Correct seasonings.
French Onion Soup Gratinee for a 3 quart tureen, serving 4-6
A loaf or 2 of firm, full-textured French bread
2 tb or more butter
3 oz firm Swiss cut into thin slices
Freshly ground pepper
2 qts simmering onion soup
4-5 tb Cognac
1-1/4 cups lightly packed, coarsely grated mixed Swiss cheeses
2 egg yolks beaten with 4-5 tb Port or Madeira
Toasted French bread rounds:
Preheat oven to 425 degrees. Cut bread into slices less than ½” thick, place in one layer on a baking sheet and dry out in upper third level of oven until fairly evenly brown.
Filling and baking the tureen:- About 45 minutes
Preheat oven to 425 degrees. Smear a tb of butter in bottom of tureen and arrange over it a closely packed layer of toasted bread. Spread over bread layer the sliced cheese, grind on pepper, ladle in the boiling soup, and pour in the Cognac. Float a closely packed layer of toast on the top of the soup and spread over it the grated cheese with a few grinds of pepper. Sprinkle over that a tb or two of melted butter. Set tureen in middle level of oven and bake for about 30 minutes. Just before serving, lift the crust with a serving fork, pour into the soup the egg yolk and wine mixture and stir gently under the crust