Don't even try this if you're on a schedule. Timing the carmelization of the onions depends on a lot of factors outside your control, like the moisture level of the onions, the pecularities of your range, and your personal caution levels. I find that it takes me well over an hour to get the caramelization right, so if I'm in a hurry and want soup, I do cream of mushroom or potage parmentier instead. That said, when you caramelize the onions properly and use a decent stock, you get the true depth of flavor you're craving. The thyme is up to you, but the bay leaves are mandatory. Use the wine, the brandy, and the Worchestershire sauce if you like bold food, and maybe drip in a little soy sauce for extra umami. I add the soy, so salt is usually unnecessary. Taste and do what seems best. I added about a tablespoon or porcini mushroom powder for extra umami when I added the stock. I had it, so I threw it in. There are a bunch of cheeses you can swap out for the gruyere if it's too much for your budget to bear, but it really does wonders for the dish. Gruyere tastes like the love child of Emmental and Cheddar, so you know it will work with onions. I had Parmagiano Reggiano, so I used it, but I probably wouldn't miss it if I left it out.
