Unwrap the pastry and sprinkle over the nutmeg, cinnamon and 2 tablespoons caster sugar. Then tightly roll up the pastry, like a Swiss roll, and cut it into 12 x 1.5 cm (3/4 inch) slices (you may have some pastry left over). Roll each slice into a small round on a lightly floured surface. Turn a 12-hole muffin tin upside down, gently press each round over the top of a muffin mould and chill in the freezer for 5 minutes.
Bake in a preheated oven, 220°C (425°F), Gas Mark 7, for 5 minutes, then place the pastry cases on a baking tray.
Meanwhile, for the filling, put the egg yolks, the caster sugar, cornflour, vanilla extract and lemon rind in a bowl and whisk until smooth. Add the cream and whisk again, then cook in a saucepan for 5 minutes, stirring frequently, until the mixture is thick, taking care not to let it boil. Spoon the custard into the pastry cases. Turn up the oven to 230°C (450°F), Gas Mark 8, and bake for 12–15 minutes until caramelized and set.