In a large skillet, melt 2 tablespoons butterover medium heat. Add ½ yellow onion (chopped) and 1 small green bell pepper (chopped), and cook until soft, about 4–5 minutes.
Add 4 oz can sliced mushrooms (drained), 1 can cream of mushroom soup, ¾ cup milk, 1 teaspoon worcestershire sauce, and ¼ –½ teaspoon salt (start with ¼ teaspoon). Stir to combine.
Add 2 cups cooked chicken (chopped) and cook for several minutes, until the chicken is heated through.
Remove from the heat and stir in ½ cup sour cream. This prevents the sour cream from curdling. Taste and add additional salt if desired.
Serve over egg noodles, rice, or mashed potatoes.
Notes
Leftovers keep in the fridge for 4–5 days and reheat nicely in the microwave or in a skillet on the stovetop. I don't recommend freezing the stroganoff, the sour cream can become grainy during the freeze/thaw process.Substitution ideas:
Several green onions (sliced) in place of the yellow onion
Fresh mushrooms instead of canned (cook with the bell pepper and onion until soft)
A jar of drained pimentos in place of the bell pepper
Turkey or ham in place of the chicken (reduce the salt if using ham)