Ingredients

200g unsalted butter, cold & cubed
80g icing (powdered) sugar
20g egg yolks (1)
225g plain (all-purpose) flour
Pinch salt
1 tsp vanilla extract

Beaten egg for egg wash
Caster or granulated sugar for rolling

Method

In a bowl, rub together the dry ingredients with the butter until they resemble fine breadcrumbs. Make a well in the centre and add your egg yolk and vanilla, gradually mixing all the ingredients together with your hand.

Tip your ingredients into a pile on a clean work surface and work the dough by using the heel of your hand, pressing the ingredients on the table and smearing them away from you. You will see the butter and flour coming together. Scrape the ingredients back into a pile in front of you, and repeat the process until there are no more dry ingredients and a dough has formed.

Divide the dough into four pieces and roll each piece into a log roughly 2cm/3/4” in diameter. Place in the freezer for 15 minutes to firm up.

Once firm, lightly brush each log with a beaten egg then roll in sugar. Cut each log into 1.5cm/1/2” pieces. Lay each piece flat side down onto a baking tray lined with paper, making sure to leave spaces between each diamant. Use your thumb to gently press into the centre of each diamant, creating a dent.

Bake at in a preheated oven at 160°C/320°F (fan oven) or 180°C/355°F (conventional oven) for 15 minutes, or until the diamants are golden.

The diamants will keep in an airtight container for up to a week.