15Combine the sugar and water in a small saucepan and bring to a boil over high heat, stirring until the sugar dissolves. Cook briskly, undisturbed, until the syrup reaches a temperature of 230 degrees F on a candy thermometer.
Remove the pan from the heat, add the coconut and butter, and stir until the butter is completely melted.
Let the mixture cool to room temp, then vigorously beat in the eggs and vanilla.
Preheat the oven to 350 degrees F.
In a small pan, melt the apricot jam over low heat, stirring constantly.
Rub the jam through a fine sieve, and brush the jam evenly over the bottom of the baked pie shell.
Pour the coconut mixture into the pie shell, spreading it smoothly. Bake for about 40 minutes.
Filling should be firm and golden brown. Before serving, arrange the thin strips of citron in a sunburst pattern in the center of the pie.
Serve warm or at room temperature; can be accompanied by whipped cream.