Preheat the oven to 200ºc/180ºc fan/400ºf/gas 6. Take your pasty sheet out of the fridge.

Heat the oil in a frying pan over a medium-low heat. Add the onions and peppers and fry for 8-10 minutes, until softened. Transfer to a medium mixing bowl.

Add in the Boursin and black pepper. Stir until the Boursin has melted and coated the vegetables.

Lay out the pastry sheet, leaving it on the baking paper. Using a sharp knife, cut into 6 even squares. Into each square, spoon the Boursin and red pepper mixture in a diagonal line from one corner to the opposite corner, stopping about ½ inch from the two corners.

Then, take one of the corners without filling and fold that over the middle of the filling. Then pull up the opposite corner, folding it over the corner already folded over and press down gently (see video for help).

Dab all exposed pastry with the egg. Carefully transfer the turnovers to a baking tray by holding onto the edges of the baking paper underneath and pulling it carefully onto the tray. Then using scissors, cut off the excess baking paper at the sides.

Bake for at the top of the oven for 20 minutes, or until the pastry golden brown.