Peel the apple, core, and chop into very small cubes. Place in a bowl and mix well with the lemon juice. Add sugar, cornstarch, cinnamon, and nutmeg and mix well to coat.

Preheat the oven to 200 degrees Celsius/ 400 degrees Fahrenheit. Butter the molds of the muffin tin very well to prevent the tart shells from sticking.

Unroll the puff pastry on the working surface, leave it on the paper it is rolled on.

Cut circles to fit the muffin pan molds, about 7.5 cm/ 3 inches. You can use a cutter or a drinking glass of the appropriate size.

Press the circles into the molds of the muffin pan. To get 12, you will have to roll the pastry scraps left over after you cut most of the circles again and cut a couple more circles.

Fill the shells with apple filling and sprinkle with chopped walnuts. Bake for about 20 minutes or until the edges of the pies are golden brown. Leave in the tin for about 5-10 minutes. Transfer to a wire rack to cool.

Sprinkle with icing sugar before serving, if desired.

Preheat the oven to 200 degrees Celsius/ 400 degrees Fahrenheit. Line a baking tray with baking paper.

Unroll the pastry on the working surface, leave it on the paper it was rolled on.

Halve the pastry vertically to get two long wide stripes. Cut the stripes horizontally to obtain 8 pieces. If the sheets are as large as those I used, they will be about 10x12 cm/ 4-4.7 inches.

Place the filling on one side, making sure you leave enough space on the side to fold the dough.

Sprinkle some chopped walnuts on top of the filling.

Fold and use a fork to seal the edges.

Beat the egg and the milk together and use the mixture to brush the pastry.

Bake for 20 – 25 minutes or until golden brown. Leave on the tray for about 5-10 minutes. Transfer to a wire rack to cool.

Sprinkle with icing sugar before serving, if desired.