This recipe was originally found in the Frugal Gourmet Immigrant Ancestors Cookbook; we modified a few of the ingredients and instructions to suit our needs. It is best served on top of "kasha", buckwheat groats.
Prepare all ingredients first, slicing and dicing. Add oil to skillet, and brown the steak on medium-high until mostly cooked.
Move steak to outside of skillet, and add the leeks, salt and pepper. Cover, and cook until slightly soggy.
Add mushrooms for a few minutes, lower heat, then slowly mix in sour cream until texture is smooth.
Remove all from heat and serve over noodles or, as recommended, kasha.