Chargrilled sirloin steak sandwich

A deliciously classic recipe from the team at Oxmantown in Dublin.

The béarnaise sauce in this dish really brings the whole sandwich together. Picture: Harry Weir and Brian Clarke

Ingredients, serves 6

6 x 120-150g sirloin or striploin steaks, no rind



For the balsamic mushrooms

8-12 large portobello mushrooms

40g balsamic vinegar

A drizzle of olive oil

80g butter, cubed

For the reduction

300ml white wine vinegar

100ml white wine

1 shallot

2 sprigs tarragon

For the béarnaise sauce

2 egg yolks

30ml reduction, see recipe

300g clarified butter, at room temperature

1 tbsp chopped tarragon

To serve

300g watercress

6 soft ...