Pre-heat your oven with the bake/broil option and heat it with your highest setting (mine is 250 C - 480 F)
Cut 2 large onions in half and thinly slice them, also thinly slice 2 cloves of garlic
Heat a stock pot with a medium heat and add 3 tablespoons of extra virgin Spanish olive oil
Once the oil get´s hot add the onions and the garlic and mix with the oil, cook the onions and garlic for about 15 minutes, stirring occasionally
Meanwhile add 3 ½ cups of vegetable broth to a pitcher, then add 1 teaspoon of soy sauce, ½ teaspoon of red wine vinegar and season with freshly cracked black pepper, mix everything together until well mixed, also cut 2 diagonal slices from a baguette that are about ½ inch thick and reserve
Once the onions have been cooking for 15 minutes, add a ¼ teaspoon of white sugar and mix with the onions, the sugar will help the onions caramelize
After cooking the onions for a total of 20 minutes, add ½ teaspoon of dried thyme, ½ teaspoon of dried parsley, season with sea salt and freshly cracked black pepper, and add ½ cup of white wine, turn the heat to a medium-high and mix everything together and cook for about 2 minutes, then add the 3 ½ cups of vegetable stock into the stock pot and mix it all together, once the stock begins to boil lower the heat to a LOW and let it simmer for exactly 15 minutes
While the soup is simmering, add the 2 slices of baguette to the oven for 5 minutes, cut a couple slices of gruyere cheese and queso Manchego, divide the slices of cheese on top of the toasted breads, season with a little dried parsley and add the slices of cheesy toast to the oven for about 8 minutes, until the cheese is melted and has a lightly browned crust on top
Divide the onion soup into 2 bowls, add a piece of the cheesy toast on top of each soup and sprinkle some dried parsley on top