Sometimes, I give a recipe without explaining what's going on. It's a habit that I sometimes find irritating in others, so I thought I'd revisit last week's beef Bourguignon, and give a few notes about what I did.
Marinating. Sometimes, marinades do not have much effect. But this one should do, because of the acid in the wine. And sugars in the wine caramelise on the surface of the meat when you brown it - so you get two effects that enhance the flavour of the dish.
Browning the onions. See this entry.
Browning the meat. See this entry (but you don't need the oil this time).
Deglazing. The liquid picks up the flavoursome, stuck bits from the pan; and, as it bubbles furiously, it loses a good part of its alcohol. Raw spirit in the dish would of course be overpowering.
Covering the meat with the liquid. In theory, the liquid will help to keep the meat tender. The gently bubbling sauce cannot get hotter than 100C; whereas exposed meat within a covered casserole may be subjected to a higher temperature. However, unless you want a thin, runny sauce, you'll need to reduce it later.
Cooking the mushrooms apart. They are the "garnish", and should be distinctive, rather than part of the stew.
In his comment below, Elwyn suggests lifting the fat from the chilled stew the following day. That would be healthier, certainly; but it also involves discarding something very flavoursome. I am inclined to leave the fat, but to serve the stew with a plain accompaniment.