I would suggest doing all the prep work before you start the cooking, as it goes together quite quickly. I don't really use a recipe, it's one I've used for years and just do it from memory.
Ingredients:
1 medium sized steak, cut into thin strips
6 large mushrooms, thinly sliced (use more if you love mushrooms)
2 onions, diced
3 cloves of garlic (or more if you want more) crushed
6 tablespoons of butter
1/4 cup of flour
2 cups of milk
250 mL sour cream
1 tablespoon tomato paste
3 teaspoons of Worcestershire sauce
Red wine (to taste) - OPTIONAL
I like to use a wok to cook this in. Have ready a deep baking dish to put all the finished ingredients.
In the wok, put 1 Tbsp butter (or margarine or olive oil) and the slices of beef. Cook over medium heat until done. Remove from the pan and place in the baking dish.
Again, in the wok with 1 Tbsp butter (or margarine or olive oil) put the onions, mushrooms & garlic and cook until mushrooms are soft and the onions translucent. Remove from the pan and put in the baking dish with the beef.
This is where it gets difficult. Melt over medium heat, 2 tablespoons of butter in the same wok (don't bother cleaning it between each use). Add in the flour to create a rue and you'll have a thick paste. Then add the milk (you may have to add more, to thin it out), stirring constantly because it'll burn quickly at this point. Add in the wine if you want, the worcestershire sauce, tomato paste, sour cream. You should have a brownish red thick sauce. Pour over the beef, onions, garlic & mushrooms in the baking dish, and cook on low heat (250 F) for about 3 hours. The meat will tenderize and fall apart in your mouth.
Serve over your noodles of choice. I like cracked black pepper on top.
Caveat: I generally don't measure when I cook or bake, so all the measurements are approximate. It's a rather forgivng recipe though, there's hardly a way to mess it up. Plus, it doubles really easy. I make it and it's enough to eat for about 3-4 days, so it'll easily feed a family of 5.
Most importantly, enjoy