Line the baking tray with parchment paper.
Assemble the Food Processor bowl onto the power unit.
Fit the Coarse (4 mm) Grating disc, attach the lid and ensure it is locked into place.

Grate butter into the Food Processor bowl using the pusher.
Remove the lid and the disc.
Transfer the grated butter into a small bowl.
Fit the Dough Tool to the Food Processor bowl.
Using the built-in scale, weigh flour into the Food Processor bowl.
Add salt into the Food Processor bowl.
Transfer the grated butter into the Food Processor bowl.
Attach the lid and ensure it is locked into place.
Pulse until roughly combined.
Mix on speed Min for 20 seconds.
While the machine is running, gradually add water into the Food Processor bowl and stop the machine.
Be careful not to over mix the dough.
Transfer the dough to a lightly floured work surface.
Bring the dough together gently with your hands.
Wrap the dough in cling film.
Refrigerate for 1 hour.

Remove the dough from the fridge.
Transfer the dough to a lightly floured work surface.
Roll the dough out into a rectangle.
Fold one end of the pastry over by two thirds.
Fold the remaining third over the top.
Wrap the dough in cling film.
Refrigerate for a further 30 minutes.
Repeat the rolling and folding process once more.
Refrigerate the dough for at least 30 minutes.

Retrieve the chilled pastry from the fridge.
Place on the prepared baking tray.
Using a small, sharp knife, gently score a 2 cm border around the edge of the pastry.
Prick the centre of the pastry with a fork.
Refrigerate until ready to use.

Clean the Food Processor bowl.
Select the 2 mm setting on the Variable Slicing Disc.
Assemble the Food Processor bowl onto the power unit.
Fit the Variable Slicing Disc, attach the lid and ensure it is locked into place.
Slice sweet potato into the Food Processor bowl using the pusher.
Transfer the sliced sweet potato into a medium bowl.
Drizzle with olive oil.
Sprinkle with salt and pepper.
Toss to combine.

Retrieve the chilled pastry from the fridge.
Spread the mascarpone mixture over the pastry within the marked border.
Working left to right; lay the strips of sliced sweet potatoes on top of the mascarpone filling, overlapping each strip on top of the one before.
Brush the edges of the pastry with egg wash.
Sprinkle poppy seeds on top.
Bake at 200ºC for 25 minutes.
Brush the sweet potatoes with a little melted butter.
Bake at 200ºC for 5 minutes.
Sprinkle with rosemary.
Bake at 200ºC for 2 minutes until golden and cooked through.
Remove from the oven.

To Serve
Cut into slices and serve hot.

Substitutions
The Emmental cheese can be substituted with 90 g of grated cheddar.