Open the scallops and rinse away any grit. Discard the top half of the shell (the half without the scallop attached). Cut the tendon that holds the scallop flesh to the shell, but leave the flesh in place. Place the scallop in its shell on a baking sheet. Repeat with the remaining scallops.
Chop the coriander, garlic and shallots. Add to the softened butter and stir in the lemon juice and ground hazelnuts.
Mix in a very little crushed sea salt and pepper.
Place equal amounts of the butter and hazelnut mixture onto the scallop shells.
Place under a grill at its highest setting and cook for 2-3 minutes, or until the scallop is sizzling and just cooked through. Take great care not to overcook the scallops.