Prepare an 8x8 inch square baking pan by lining it with parchment paper, ensuring some overhang for easy removal later.

In a large bowl, combine the desiccated coconut, crushed biscuits, and the finely chopped dried apricots.

Pour the melted butter over the dry mixture and stir thoroughly until everything is evenly moistened and combined. It should hold together when pressed.

Press the mixture firmly and evenly into the prepared pan. Use the bottom of a glass to ensure the base is compact. Place the pan in the refrigerator to chill for at least 30 minutes while preparing the topping.

Melt the white chocolate using a double boiler or in the microwave on short bursts, stirring frequently until smooth. Allow it to cool slightly (about 5 minutes) so it doesn't melt the base.

Gently spread the apricot jam evenly over the chilled base. Then, pour the slightly cooled melted white chocolate over the jam layer, spreading it to cover the entire slice evenly.

If using, sprinkle the toasted coconut evenly over the melted chocolate. Return the slice to the refrigerator and chill for a minimum of 2 hours, or until the chocolate has set completely firm.

Once set, use the parchment paper overhang to lift the slice from the pan. Cut into 16 even squares using a sharp, warm knife.