French onion soup : really really cook the onions hot and long, I pretty much always don't do it long enough or hot enough. Broth should be much richer than you think it needs to be because the bread and cheese are mildening agents. Need good beef broth. If your broth is shitty, you can cheat and punch it up with Worcestershire.
French apple tart : it's easiest to just blind bake the tart crust and cook the apples in a pan seperately, and then put together. You want quite a thick crust, like double the thickness of an american pie crust; the star of the tart is really the crust, the apples are just like a topping on the sweet buttery pastry. Also glaze the crust before putting on apples, it will harden the boundary. Between the crust and the apples you want to have a bit of glue, a thin layer of something that will bake firm and absorb flavor, like an apple sauce + ground almond paste. To get a good caramelization you want to foil the edges of the tart and broil. The secret to the real french glisten is lots and lots of butter (during baking) and lots and lots of glazing with apricot jam (at the end), way more than you think.
The right fat % for hamburgers is somewhere around 12%. More is gross oily, less is nasty dry. The "Kosher" ground beef at TJ's seems just about perfect. The other stuff they sell is too lean or too fat. I guess if you were really fancy you could grink your own and add some nice fat to just the right amount.
How to prep garlic : first of all, a "clove" is one little piece of a head of garlic, a "head" is a bunch of cloves. I saw a couple in a grocery store the other day in line in front of me, the guy asks his girl to run and grab a clove of garlic (wrong), she actually runs off and comes back holding one clove (dumb, obviously he meant a head). I hate it when people react to what you actually said and not what you obviously meant. Anyhoo. Take a clove (skin still on) and cut off the stem end, you only need to cut about a tenth of a centimeter off. You don't want to eat the stem end, but mainly this is to release the skin. Lightly bash the clove. Personally I don't like to bash with my chef's knife because I've found over time I've been putting slight bends in my knife from bashing garlic and it's not perfectly straight any more. If you are into silly unitaskers like Alton Brown is, you can use a hunk of granite. I find board scrapers are a very useful tool and make good garlic bashers too. Mostly I just use the heel of my hand. You aren't trying to crush to a pulp here, just a light bash. The skin should now pop right off. At this point you have various options. For a very fine dice you can use a garlic press. I think there are very few dishes where that is actually the right cut for garlic; it is the way to go generally for asian garlic use. For most applications you just want to dice with a knife, which produces a controllable size and larger pieces which cook sweeter and without the bite of crushed garlic. To make thin garlic flakes, if your knife skills are not super top notch the easier way is to use a vegetable peeler. Garlic flakes fry quickly and make a lovely garnish for garlic dishes.
BTW something I've learned from Jamie Oliver is that you can use garlic very nicely with the skin on. Take a clove, and cut off the stem end as usual which will make it easy to squeeze out later. Now when making a roast, such as oven roasted carrots or brussel sprouts, or a roast shoulder of lamb, or whatever, just toss a bunch of skin-on cloves in the mix. 40 minutes at 400 or whatever and you'll have nice roast garlic, which will also have perfumed whatever you roasted. The skin keeps the outsides from burning which it would do if you took the skin off in these applications.
Sugar is a cruel temptress. In the last 2 weeks I've had : Joy of Baking molten chocolate cake, Jacques' brownies (+ lots of plain roasted hazelnuts, yum), Nigella's chocolate chunk cookies, carrot cake (thanks babe), banana bread, banana banana bread bread pudding (lol, parse that beeyotch) (aka banana bread banana bread pudding), french apple tart, in addition to lots of tartines (aka bread with jam) and some chocolate. And when I say "brownies" I don't mean like one or two, I mean a batch. Work used to provide a good outlet for my bad baking habit, because I could make a batch, eat a few, and take the rest to work. Now I have to eat them all myself.