1. Preheat the oven to 180°C.

2. To make the herb crust, lightly toast the bread, remove crusts and process into breadcrumbs. Caramelise the palm sugar in a saucepan over medium-high heat (about 3 minutes, stirring occasionally). Remove from heat, add the fish sauce, stir to combine and allow to cool. Place all the other ingredients in another bowl with the breadcrumbs and add the cooled palm sugar mixture. Mix until the crust sticks together. Place mixture between two sheets of baking paper and flatten on a bench until about 5mm thick. Refrigerate until needed.

3. To make the potato gratin, cut the potatoes into 1mm slices. Butter a 30cm x 20cm baking tray and place the sliced potatoes in a line along the tray, overlapping slightly. There should be about three layers.

4. Gently melt remaining butter, mix with cream and pour mixture over potato slices. Season with salt and pepper. Cook in the preheated oven for 40 minutes, or until the cream has been absorbed and the potatoes have browned. Remove from oven and keep warm.

5. Meanwhile, to prepare the fish, remove baking paper from the herb crust, place the fillets on top and cut crust to fit each piece of fish. Line an oven tray with baking paper. Slide an egg flip under the crust, turn over so the crust is on top of the fish and place on lined tray, crust side up.

6. Bake fish in preheated oven for about 10 minutes or until just cooked. Turn off the oven, open oven door and rest for 2 minutes.

7. To serve, cut the gratin into four pieces about the same size as the fish. Remove the fish from the oven, place a piece on each plate with a squeeze of lemon. Top each with a piece of gratin and serve immediately with a green salad.

If you like this recipe, try Neil Perry's Chilli salt prawns