This is what I did:
Chicken pieces (or beef, lamb, pork)
1 or 2 onions, minced (food processor, or hand held device)
hot tomato sauce
soured cream* (see below for recipe)
Of course you can buy soured cream but as you only need a tbsp or two, you then have to find further uses. I had double cream lite in the fridge, so I wanted to use that.
1 cup of cream
1 tbsp of lemon
1 tbsp of vinegar
Mix lemon and vinegar, then start whipping the cream, adding the mix 1 teaspoon at a time.
It isn't quite the same but it'll do as a substitute.
Next up will be my Iberian Casserole...