Spray an 8x8 inch square pan with cooking spray. Lay a double layer of cling film into the pan and then spray that with cooking spray too.
Place the condensed milk, white chocolate, lemon zest and coconut extract into a deep saucepan, over a low heat.
As the mixture begins to melt, add in a few drops of yellow food colouring. I ended up putting a little too much in there and then had to use an icing lightener, so be careful! You can make it as pale or vibrant as you like.
Stir the mixture until everything is melted and smooth, then add 1tbsp of butter and stir until melted. Add in 2tbsp of desiccated coconut.
Pour the mixture into your prepared pan and smooth into an even layer. Leave to cool for 2 minutes and then sprinkle the 1/2 cup of desiccated coconut all over the top of the fudge.
Leave to cool to room temperature, before putting in the fridge to chill. This will take around 4 hours, but you can just leave it over night.
Transfer the fudge to a cutting board and get a jug of warm water, kitchen roll and a long knife ready.
Dip the knife into the warm water, dry it off and then slice the fudge into 16-24 squares. I usually manage 2-3 cuts before having to re-warm the knife. A warm knife makes it SO much easier to slice!
Lemon and Coconut Fudge can be kept in an airtight container, in the fridge, for 2 weeks. You can place fudge into cellophane bags, tie with a ribbon and give as gifts or just devour it all yourself!