Step by step recipe:

1. 2 min.

   Toasting the flour

   Preheat the oven to 360°F (180°C), if possible, without the fan.
   
   Spread 250 g flour out on a baking sheet in a thin and even layer.
2. 10 min.
   Put in the oven for 10 minutes. Watch carefully - the flour should stay white, not take on any colour.
   
   Take out of the oven and leave to cool.
3. 5 min.

   Make the biscuit dough

   Put into a food-mixer bowl: 100 g butter (cut into small pieces), 125 g caster sugar, 2 eggs, 2 pinches salt and the toasted flour when cooled (tip this straight into the bowl).
4. 3 min.
   Mix until the dough is evenly mixed.
5. 2 hours
   Tip the dough out onto a large sheet of plastic film, roll it into a large "sausage" and wrap in the film.
   
   Refrigerate the dough for 2 hours or overnight.
6. 5 min.

   Cooking

   Preheat the oven to 360°F (180°C).
   
   Unwrap the roll of dough and slice into rounds about 1/4 inch (5 mm) thick.
7. 3 min.
   Lay the slices on a baking sheet and use a brush to glaze them with beaten egg.
8. 15 min.
   Bake for 15 to 20 minutes, watching the colour carefully.
9. 
   Leave to cool on a wire rack.