Dampen an 18 cm (7 inch) square, loose-based shallow tin or cake tin and line with a square of cling-film that comes up and over the sides. Crush the biscuits in a polythene bag with a rolling pin. Mix with the melted butter and tip into the tin, pressing down well.
Pour the coconut milk and cream into a saucepan and heat gently until bubbling around the edges. Put the eggs, egg yolks, sugar, flour and rosewater in a bowl and whisk until smooth. Pour the warmed milk over the egg mixture, whisking well. Strain through a sieve into a jug and spoon carefully over the biscuit base. Place a roasting tin of hot water on the lower oven shelf and place the tin on the upper shelf. Bake at 160°C (325°F), Gas Mark 3, for 35 minutes until the surface feels set but is still slightly wobbly. Leave to cool in the tin.
Put the Turkish delight in a small saucepan with 2 tablespoons water and heat gently to melt, stirring often. Add a little water if it evaporates. Add a drop of pink food colouring, drizzle the syrup over and cut into squares.