Lingkan Reang
Preheat the oven to 190°C (170°C fan) and line a 20 x 30cm cake tin with baking parchment.
Melt butter with sugar, syrup, and coffee, then mix in walnuts, oats, flour, and a pinch of salt.
Press the mixture into the tin and bake for 25 minutes, let cool.
For the icing, melt butter with coffee and mix with the icing sugar until smooth.
Spread icing over cooled flapjacks, placing walnut halves and chopped walnuts on top.
Allow icing to set, store in an airtight container for up to a week.