I have a great recipe, not for slow cooker but you could probably adapt it. Just posted it the other day on here, it uses red wine.
Ok. Hope I can translate this correctly. It is a German recipe, very traditional one. Goes well with pork and poultry, particularly goose and duck.
Rotkohl nach Mutters Art - Mama's Red Cabbage
1kg red cabbage (I use a whole one)
1 large onion
3 sour apples
60g goose fat
1 bay leaf
cloves
salt
2 dsp white wine vinegar
125ml water (or white/red wine)
1 dsp plain flour
2 dsp water
2 dsp blackcurrant gelee (optional)
Wash and slice the cabbage, very finely. Chop the onion and the apples.
Saute the onion and the cabbage in the goose fat then add the apple, bay leaf, a couple of cloves, salt, sugar, vinegar and the gelee. Add the water and simmer for 2 hours with lid on, at a low heat.
Mix the flour with 2 dsp water and use this to thicken the sauce.
Yum yum yum.
I make a huge batch and freeze some.