Lime and Coconut Meringue Pie

For the pastry

unsalted butter, softened, plus extra for greasing

medium free-range egg yolk

icing sugar

coconut flavoring

plain flour, plus extra for dusting

free-range egg, beaten

For the filling

large free-range eggs

large free-range egg yolks (reserve the whites for the topping)

caster sugar

limes, juice and zest only

unwaxed lemon, juice and zest only

double cream

green coloring (optional)

For the topping

large free-range egg whites

caster sugar

desiccated coconut

flaked coconut, to decorate