Zoervleisj (Dutch=zuurvlees, English= (literally) sour meat) is a horse meat stew from Limburg, the southern-most of the twelve provinces of the Netherlands. Since horse meat is quite difficult to buy nowadays you can use beef instead.
Marinate 500 gram cubed beef in water and vinegar (50/50). For 500 gram I used 200 ml water and 200 ml vinegar. Add 6 bay leaf and 6 juniper berries. Marinate overnight or 8 hours. Horse meat needs to marinate longer. You can also marinate two onions together with the meat. Otherwise cut two onions just before cooking. I used plain vinegar (natuurazijn).
The next day:
Dry the meat, discard the juniper berries and keep the bay leafs and marinade liquid.
Fry the meat in hot butter until brown.
Heat the marinade liquid, bay leafs, 4 cloves in a cooking pot. Cold marinate can make the meat tough (apparently). Add the meat and stew for one hour.
In the meantime fry the onion in butter over a low fire until brown.
Add the onions to the cooking pot and 2-3 tablespoons appelstroop (=apple butter).
Stew for another hour and add 2-3 slices of ontbijtkoek. Crumble the ontbijtkoek and stew for another hour or so.
The ontbijtkoek makes the sauce thick so stir regularly from this point onwards. Adjust the taste (salt, sugar). Aim for a distinct sweet and sour taste, but just a bit more sour than sweet.
Serve with homemade fries and apple sauce.