Cut the butter into cubes and leave at room temperature to soften.
Skin and bone the salmon.
Trim, peel the shallot and finely slice.
Grease the baking tray and line with parchment paper.
Lift the Cooking Chef head and fit the heat shield.
Fit the Spiral Dough Tool to the machine.
Attach the Cooking Chef bowl to the machine.
Add the first 3 items of Ingredients 1 (flour, salt, water) into the Cooking Chef bowl, fit the splash guard.
Mix on speed 1 for about 2 minutes until combined.
With the machine is running, gradually add the remaining items of Ingredients 1 (butter) to the bowl.
Mix on speed 6 for 6 minutes.
Transfer pastry to a clean worksurface.
Wrap with plastic wrap.
Chill in the fridge for 1 hour.
Transfer pastry to a lightly floured worksurface.
Roll pastry out into rectangle, about 3 mm in thickness.
Add Ingredients 2 (butter) over the top two-thirds of the pastry.
Fold the bottom unbuttered third up over the centre.
Fold the top third over the rest of the pastry.
Turn the pastry over and seal the edges with a rolling pin.
Chill in the fridge for 15 minutes.
Repeat the rolling, folding and chilling process 3 more times.
Roll out the pastry until 4 mm thick.
Cut out two rectangles about 18 cm x 21 cm in size.
Transfer pastry onto the lined baking tray.
Prick one of the rectangles all over with a fork.
Using a sharp knife, score lightly with a crisscross pattern on the second rectangle.
Chill in the fridge.
Preheat an oven to 200ºC.
Retrieve, clean the Cooking Chef bowl.
Add the first item of Ingredients 3 (water) into the Cooking Chef bowl.
Place the remaining item of Ingredients 3 (fish) into the steamer basket.
Place the steamer basket into the Cooking Chef bowl.
Steam at 100ºC for 20 minutes.
Carefully remove the steaming basket, cover with foil and set aside.
Remove the pastry from the fridge.
Brush the top pastry rectangle with Ingredients 5 (egg).
Bake for 15 minutes at 200ºC until golden brown.
Remove from the oven and place the pricked layer of pastry onto a serving plate.
Retrieve, clean the Cooking Chef bowl and fit the Stir Tool.
Attach the Cooking Chef bowl to the machine and fit the Stir Assist Clip.
Add the first item of Ingredients 5 (oil) into the Cooking Chef bowl.
Heat at 120ºC, on speed Stir 1 for 1 minute.
Add the rest of Ingredients 5 (shallot) to the bowl.
Cook at 110ºC, on speed Stir 1 for 1 minute.
Add Ingredients 6 (wine, stock) to the bowl.
Cook at 120ºC, on speed Stir 1 for 8 minutes.
Add Ingredients 7 (cream, mustards, spinach) to the bowl.
Cook at 110ºC, on speed Stir 1 for 6 minutes.
Use tongs to remove the spinach from the sauce and place on top of the pastry base.
Add the first item of Ingredients 8 (cornflour) to the small bowl.
Cook at 110ºC, on speed Stir 1 for 8 minutes until thickened.
Add the remaining items of Ingredients 8 (seasoning, lemon) to the bowl.
Cook at 62ºC, on speed 1 for 5 minutes.
Transfer sauce to a jug.
Remove the fish from the steamer basket and flake into large chunks.
Place the fish on top of the spinach.
Place the pastry top on top of the fish.
Serve.