Firstly, preheat the oven to 180C/160C Fan/Gas Mark 4. Then line three baking trays with baking paper and set aside.
Place the butter, sugar and golden syrup into a medium saucepan and heat gently until the butter is melted, stirring a couple of times. Remove from the heat and stir in the flour until combined. Then stir in the chopped nuts and fruit, until well combined.
This recipe makes 18 florentines, so you want to scoop six heaped teaspoonfuls of the mixture onto each baking tray, leaving space between each to spread. Then bake them in the oven for 8-10 minutes, until golden brown. Leave the florentines to cool on the tray, before placing them onto a cooling rack. (If don’t have enough space in the oven for three trays at once, get them spooned onto the trays in preparation, as mixture will begin to harden a little in the saucepan.)
To decorate: Melt the dark chocolate either in a microwave in 30 second increments (stirring between each), or over a bain-marie (a saucepan filled with water, with a heat-proof bowl sat on top that doesn't touch the water). Then carefully spread the melted chocolate over the base of each florentine - I used a silicone pastry brush for ease - then leave to set for a minute or so. Then using a fork, make a zigzag pattern in the chocolate and leave to set on the cooling rack, chocolate side up.
Notes
Florentines can be kept in an air-tight container at room temperature for up to one month.