Eggs Benedict with smoked salmon & chives

INGREDIENTS

• 4 eggs
• 2 tbsp white wine vinegar
• 2 English muffins , halved
• a little butter , for spreading
• 8 slices smoked salmon
• chopped chives , to serve
• 2 tsp lemon juice
• 2 tsp white wine vinegar
• 3 egg yolks
• 125g unsalted butter , diced