Spread softened butter all over the bottom of crockpot, then add beef and toss with cornstarch.
Add remaining ingredients except for sour cream, egg noodles and parsley/chives to crock pot, stirring well.
Cook on high for 4 hours, or on low for 6 hours, stirring a few times.
In the last 10 minutes of the beef mixture cooking, boil egg noodles for 5 minutes on the stove, then drain and set aside.
Once cook time has finished, stir in sour cream and mix to combine well, then gently stir in hot egg noodles.
Let the mixture sit with the lid on for 5 minutes (sauce will thicken up this way) then serve with parsley or chives overtop (optional) and enjoy!
