Preheat the oven to 425°F (400°F for fan forced ovens). Cook Quorn Meatless Roast in the oven from frozen, according to package directions.
Duxelles (Mushroom Stuffing): add mushrooms, thyme and shallots to a food processor until finely chopped. Put a frying pan on medium heat and melt 2 tbsp butter. Once melted, add mushroom mixture to pan and cook for roughly 25 minutes until all liquid has cooked out. Add salt and pepper to taste and set aside in the fridge to cool.
To assemble the Quorn Wellington, sprinkle flour on a clean countertop and place 2 sheets of thawed puff pastry on top of each other. Roll out slightly with a rolling pin. Spoon on cooled duxelles, and spread evenly in a thin layer across the pastry sheets, leaving an inch of pastry on each side.
Once Quorn Roast is cooked, allow to cool slightly. Then coat in Dijon mustard and place on the bottom edge of the puff pastry.
Meanwhile, melt 2 tbsps of butter and set aside. Brush the other three edges of pastry with melted butter and roll Quorn Roast so that it is covered in pastry.
Press down edges of pastry (trim any excess pastry if required) and ensure that they are sealed. Wrap tightly in cling wrap and set aside in the fridge to chill for 30 minutes.
Meanwhile, line a baking tray with parchment paper or tin foil to prevent the Quorn Wellington from sticking and reheat oven to 425°C (400°F for fan forced ovens)
Once cooled, remove Quorn Wellington from the fridge and place in the lined baking tray. Pierce puff pastry with knife and then brush egg wash over roast. Sprinkle top with flaked sea salt.
Put in the oven to bake for 30-40 minutes, until the pastry is golden in color. Set aside Quorn Wellington for 10 minutes before serving, to allow it to rest. Then slice and serve!
Tip: Serve along with roasted potatoes, Brussels sprouts and carrots.