Preheat the oven to 180C/gas 4/fan
160C and generously butter a 28 x 8cm
shallow baking tin. Melt the butter, sugar
and syrup over a medium heat, stirring all
the time. Take off the heat and stir in the
oats, walnuts and orange zest. The
mixture should be quite soft.
Tip the mixture into the baking tin and
level it off. Bake for around 30 minutes or
until the edges are golden brown but the
centre is still a little soft. Remove from the
oven and mark into 12 pieces while it is still
warm, cutting down halfway through the
mixture with a sharp knife. Leave to cool.
Heat the marmalade with 1 tbsp water
until it becomes syrupy. Brush this glaze
over the flapjack mixture and leave to cool
before cutting into 12 pieces. They will
keep in an airtight tin for up to a week.