I think it is probably impossible to reproduce at home the brioche you can buy in the boulangerie-pâtisserie, but you can certainly produce something with more character than the supermarket version.
Brioche these days is well-known for being the 'cake' Marie-Antoinette suggested the populace ate in the absence of bread (although some sources point out that as an Austrian, she may actually have referred to Kugelhopf). C'est la même farine - the issue is she was having a blonde day and they are leavened breads enriched with egg and fat to produce a treat, not everyday fare, unless you were rich.
I used Andrew Whitley's recipe from Bread Matters. Like Hugh Fearnley-Whittingstall's Meat, this is part polemic, part recipe collection, aptly subtitled 'the state of modern breadmaking and a definitive guide to baking your own'. I can recommend it, although you may never be able to face supermarket bread again. The discussion and instructions for brioche covers six pages (the recipe proper takes up four of these). He begins by saying: 'Making brioche by hand is an experience: it's pleasantly energetic, and quite a challenge to incorporate so much butter into a seemingly unwilling dough. Eating it is the reward for trusting in a favourable result when all the evidence seems to suggest disaster. Doing it yourself means that you can avoid the strange compound fats that are used to eke out expensive dairy butter in [supermarket] brioche, not to mention the gratuitous additives that make it look good and 'keep' for an improbably long time. If you make it yourself, you can eat it genuinely fresh.'Incorporating the butter into the dough is done by squishing and stretching the mixture between the hands for about 15 minutes. It is not kneaded on the bench like an ordinary bread.It's a good idea to prove the dough overnight in the fridge. It makes it more manageable when shaping for the tin, and means you can produce it warm for breakfast. It is not necessary ( or worth it for home baking) to put the dough in a special brioche mould. Here I have made four mounds which will merge together somewhat once proved and cooked. Simon was worried that the tin was not very photogenic, but my feeling is that it is an honest, good quality, well-used tin.The end result looks and tastes rather like fruitless, spiceless Chelsea buns (but better than that sounds). This brioche is not sweet, but ideal for tearing up and dipping into chocolat chaud* before eating.
*The hot chocolate is in a mug made by my Australian potter friends Ricky, Elise and Gillian.