Lightly spray a 9" loose bottomed cake/flan tin.
Melt the butter in the microwave. Meanwhile crush the biscuits (with a rolling pin or in a food processor) until it resembles breadcrumb texture.
Combine the crushed biscuits with the melted butter. Press into the bottom of the pan, using the bottom of a glass or the back of a spoon.
Chop the chocolate into small pieces. Meanwhile, heat the coconut milk in a medium saucepan over a low/medium heat.
Once the coconut milk is simmering, turn off the heat and add the chocolate. Leave for 2 minutes then stir together until all the chocolate has melted and the mixture has thickened (it will be a glossy chocolate colour).
Pour this over the biscuit base. Chill for 1-2 hours, until the top has set (the chocolate layer will not truly set, but be somewhat firm to touch).
Once set, create a ring of jam on top of the chocolate ganache using the back of a teaspoon to spread it.
Optional: Toast the coconut flakes in a small frying pan over a medium heat. Sprinkle over the jam.
Slice when ready! If making ahead, place back in the fridge until serving.