Instructions: Measure the flour sugars butter semolina and grated orange and lemon rinds into a processor and process until thoroughly combined. (This can be done by hand rubbing the butter into the flour first then adding the other ingredients and working together to form a ball.)

Press the shortbread mixture into the large roasting tin and level with the back of a spoon so that the mixture is the same depth all the way across.

Sprinkle evenly with the dernerara sugar and flaked almonds.

Slide the tin on to the lowest set of runners in the roasting oven with the plain cold shel fon the second set of runners for about 10 minutes until a pale golden colour (turning round halfway through if necessary).

Do watch very carefully.

Transfer the tin to the simmering oven for a further 30 to 40 minutes until the shortbread is cooked through.

Bake in the baking oven on the lowest set of runners for 10 minutes.

Slide in the cold plain shelf on the second set of runners for a further 15 minutes then transfer to the simmering oven for a further 10 to 15 minutes until cooked.

Remove from the oven and allow to cool for a few minutes then gently cut across by 6 and by 4 and cut each square in half diagonally.

Lift out and leave to cool on a cooling rack.

The plain version is always served at our aga workshops and is so popular we have done this variation from time to time.

Makes 48 triangular biscuits

If you would like to email yourself the recipe for later use, or share the recipe with your friends or family, enter the email addresses below and this recipe will be emailed to you and others as well.