Here's the blueprint:
good cut of beef, top sirloin, roast, ribeye steak, whatever you got
onions or shallots
beef stock cube (I use Knorr)
I sauté the sliced onions or shallots in butter until soft. Then I add the beef which has been sliced into strips. After the beef has cooked for a while I add the mushrooms, stock cube, some water and red wine and let it simmer for a while, maybe 40 minutes or so. Then I add some tomato paste, stir and add more water if it looks too thick and let it go for another 20-30 minutes, checking occasionally that it's not drying out or sticking.
I serve the Strog over rice with a dollop of sour cream, but it's fine without.
You have a lot of flexibility with the Strog sauce, that is, the water and wine and tomato paste. If it's too thick add some water. If you add too much water you can either cook it down or add some corn starch (mixed with a little water) to thicken it. It's a very flexible recipe and can be stretched to feed a crew.
I have read that a really proper Beef Stroganoff calls for a very good cut of beef cut against the grain into thin slices, and the entire cooking process is very quick. Basically, searing the meat and onions, then creating a sauce with tomato paste, water, wine or brandy very quickly and reducing it to a sauce. I once tried to cook Strog like this using filet mignon, shallots and brandy and although the result was very good, the cooking was quite frantic and the dish was not that memorable from the more pedestrian version I've described.
When it comes to flavor, color, texture and taste, flavor and yummyness I don't think you can beat Beef Strog. I'd go have a second helping right now, except I know it's all gone. All that remains is the memory.
p.s. The candle is on the dish because the kitchen light burnt out and I didn't fix it because I was working with the garage door people to fix the broken garage door spring. Priorities, people, priorities!