Posh fish pie

Ingredients

• 50 millilitre olive oil
• 3 large red onions, finely sliced
• 6 clove garlic, peeled and sliced
• 2 400g cans whole peeled tomatoes
• 2 tablespoon capers
• 1 cup pitted green olives, halved
• 3 bay leaves
• 8 thyme sprigs
• 1/2 cup finely chopped flat-leaf parsley
• 4 sheets puff pastry
• 400 gram blue-eye trevalla fillets, skin removed, cut into 2cm chunks
• 1 egg, beaten
• mixed salad leaves, to serve