Smoked salmon hash brown with poached egg and hollandaise

Name: Smoked salmon hash brown with poached egg and hollandaise
Ingredients: 50ml/2fl oz white wine vinegar; 6 peppercorns; 1 bay leaf; 1 sprig tarragon; 2 egg yolks; 110g/4oz clarified butter, warmed; 1 lemon, juice only; 1 tbsp gluten-free wholegrain mustard; pinch cayenne pepper; 1kg/2lb 4oz cooked potato, slightly mashed; 400g/14oz cooked salmon fillet; 150g/5½oz smoked salmon, torn into pieces; 150g/5½oz crème fraiche; 2 tbsp chopped dill; 75g/2½oz unsalted butter; salt, to taste; 1 tbsp white wine vinegar; 4 free-range eggs