Make the cookie dough

• Cream the softened butter with the brown sugar and granulated sugar until light and fluffy.
• Beat in the egg and vanilla extract until smooth.
• Whisk together the flour, baking soda, salt and cinnamon, then fold into the wet mixture to form a soft dough.

Chill the dough

• Wrap or cover the dough and chill it so it firms up and is easier to press into the dish.

Assemble the pie

• Press about two thirds of the dough into the pie dish, covering the base and up the sides.
• Spread the Nutella over the dough, leaving a small border.
• Flatten the remaining dough into pieces and place them over the Nutella to cover the filling.

Bake

• Bake in a preheated oven at 180 °C until the edges are golden and the centre is just set.

Coat with cinnamon sugar

• Mix the sugar with the cinnamon.
• Brush the warm pie lightly with melted butter and sprinkle the cinnamon sugar generously over the top.
• Let it cool slightly before slicing.