Try using a combination of different mushrooms as well as the flat mushrooms.
2 tbsp olive oil plus extra for brushing
2 shallots, thinly sliced
3 cloves garlic, crushed
4 large flat mushrooms, thickly sliced (350g)
2 tsp balsamic vinegar
½ x 25g pack flat leaf parsley, chopped
½ tsp LoSalt
125g ciabatta loaf, halved horizontally
1. Heat the oil in a large frying pan and fry the shallots for 2 minutes. Add the garlic and mushrooms and fry for 3-4 minutes, adding 50ml water. Stir in the vinegar, most of the parsley and LoSalt and cook for 1 minute.
2. Brush the cut surface of the ciabatta with a little oil and griddle for 1-2 minutes until golden. Top with the mushrooms and sprinkle with the remaining parsley to serve.