Mix the melted butter with the flaked chillies, chopped sorrel, add some salt and the crushed black peppercorns.
Roll the salmon in the butter and herbs mixture and ensure that its well coated.
Slice the lemon into wedges removing any pips.
Preheat a griddle pan and transfer the remainder of the butter and herbs to the pan. When its spitting, add the salmon fillets and grill for 6-8 minutes turning once to ensure even browning. Cook the lemon wedges in the griddle pan until they start to brown.
Meanwhile bring a large flat pan of water about 3-4 cm deep to the boil, add a little salt.
Place the asparagus into the pan, turn the heat down and simmer very gently for 8-10 minutes until tender but not overcooked. Drain.
Serve the salmon on a bed of asparagus, and garnish with lemon wedges. Pour the remaining butter and herbs over the asparagus.