The only way this could get better would be to have it with bacon...
1/4 cup (60 ml) dry white wine
1/4 cup (60ml) white wine vinegar
1/2 a small onion - thinly sliced
4 tsp lemon juice
200g butter - chopped and chilled
Put the wine and vinegar into a small pot and bring to the boil.
Add the onion, season and reduce the heat to low.
Cook until most of the liquid has evaporated - you need to leave about 1 - 2 tbsp.
Add 2 tsp lemon juice then strain - keep the liquid.
Return the liquid to a clean pot and bring back to hot.
Turn the heat down again and whisk in the butter piece by piece - wait until each piece is melted before you add the next - keep whisking.
Add the remaining 2 tsp lemon juice, season to taste and keep warm.
Pan fry your fish in butter.
Serve fish with sauce spooned over. We had ours with zuchinni, Rick had potatoes too.