To make the apricot chia jam, place apricots, water and honey into a saucepan over medium heat. Bring to the boil, reduce heat and simmer, covered for 10 minutes or until apricots are soft. Mash with a fork until smooth. Add chia seeds and stir until combined. Cool. Place in an airtight container in the fridge until needed.
Preheat oven to 180°C/160°C fan forced. Grease and line a 30cm x 20cm slab pan with baking paper. Using an electric beater, beat butter, sugar and vanilla until light and fluffy. Add egg and beat until just combined. Stir flour and desiccated coconut into butter mixture. Spoon mixture into prepared pan and spread evenly with the back of a spoon. Bake for 15 minutes or until light golden. Cool.
Spread apricot jam over slice. Combine shredded coconut and extra sugar in a bowl. Add the extra egg and stir until combined. Spoon and spread mixture over jam. Bake for 25 minutes or until golden. Cool. Remove from cake pan and cut into fingers to serve.