This was awesome! I usually use round steak but had a sirloin and wanted to find a sirloin-specific recipe. I like this even better than my usual which I love, so this will be my new go-to thanks!! I did do a couple of things differently for my family's tastes: I deglazed the pan after searing the meat with a couple glugs of good red wine and then poured the reduced wine over the meat and veg. I also omitted the tomato paste, used chicken stock (what I had) and added a Tbs of beef boullion. It was so so good even without the sour cream. Served over egg noodles with roasted asparagus on the side.
Shortcut or not, this turned out really great! I added two extra smashed garlic cloves while cooking and removed before serving, (I love garlic!) and I did use round steak as that is what my daughter-in-law had at her house. This was really easy to make...and I will do it again for my students at home. I personally don't consume beef anymore, but had to have it for taste. Yummy! Think that it can carry more onion, if you like onions! Oh, forgot, didn't use the wine as I didn't want to open a bottle for just 2 tbls full.