Put the onion, half the lemon juice, the brandy and peppercorns in a shallow pan with about 400ml of water – just enough to cover the salmon when you add it; bring to the boil and simmer for 10 minutes; add the salmon fillet and gently poach for 4-5 minutes; cool in the poaching liquid
Lift the salmon out of its poaching liquid, remove the skin and flake the flesh; mix with the smoked salmon, the remaining lemon juice, lemon rind, the melted butter, 3 tablespoons crème fraiche and 1 tablespoon dill fronds chopped; season to taste; divide between 8 x 150ml dishes or ramekins
Mix the 200ml crème fraiche with the rest of the dill fronds; top each salmon pate with the crème fraiche and garnish with some dill fronds; serve with some melba toast
8 servings