Onion soup & Tears

My parents are abroad for the week, and I'm alone in the house with my brother. For some reason, this is the week my dear brother decides to get sick and have a math test. Of course my mother assumes, that since I did my mathematics matriculation only three years ago, I remember how to help him, why wouldn't I? I hated math. Why does everything have to go wrong when my mother's gone? Because my mother is one of those people blessed by the gods. She never gets sick, and things always work out for her. True story, she was once stranded in the middle of the desert (her car broke down) and a limousine picked her up, and just happened to be going where she was going, and it wasn't some crazy freak. This also happened to be one of the only guys in Israel with a cellphone at that time (this was 8 years back). I, on the other hand, am not quite as lucky, although I have received the occasional discount for no obvious reason at pizza hut. The truth, taking care of my brother is not so bad, and he liked my soup. Now, I know I promised chicken soup, but I changed my mind, deal with it. Here's the (approximate) recipe for onion & tomato soup:

Melt butter (or olive oil) in a pot (or a wok). Take two large onions (or maybe three - depending on how fresh they are) and slice them thinly. Slice about three (or four, more then the onions) tomatoes. Fry (on a low flame) the onions and the tomatoes, until the onions are clear (about ten minutes), while stirring. Add two teaspoons of salt (you can always add more later), one teaspoon of dry mustard, and a dash of ginger. Stir some more. Add about four cups of water, and some pepper. Cover and wait for it to boil. Now you can add two tablespoons of soy sauce and\or one tablespoon of dry white wine (I forgot to, so I can't tell you what the results were). Let simmer for ten-fifteen minutes, stirring every now and again. Eat. It tastes quite good, and if you sprinkle mozzarella it tastes even better. Bon appetite.