01 -
Combine butter, cheese, mustard, and egg yolk together. Add the salt, sugar, and flour, then knead it all into a dough.
02 -
Wrap the dough in plastic wrap and pop it in the fridge for 2 hours.
03 -
Roll the dough flat and cut out rectangles measuring about 2-3 cm by 5-6 cm.
04 -
Bake for 13-15 minutes at 190°C (fan) or 200°C until golden brown.
05 -
Let the biscuits cool down on a wire rack before serving.