Put the butter, sugar and syrup in a saucepan and heat gently until just melted. Remove the pan from the heat and stir in all the remaining ingredients. Tip the mixture into an 18 x 28 cm (7 x 11 inch) roasting tin lined with nonstick baking paper (see
Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 25–30 minutes until golden brown and just beginning to darken around the edges. Leave to cool for 10 minutes then mark into 16 bars and leave to cool completely.
Lift the paper out of the tin, cut the bars right through and peel off the paper. Store in an airtight tin for up to 3 days – they are energy boosters and therefore ideal for adding to lunchboxes.