|Butter/Margarine||6 Ounce, softened (About 175 Gram)|
|Caster sugar||6 Ounce (About 175 Gram)|
|Egg||1 , beaten|
|Plain flour||12 Ounce, sifted (About 350 Gram)|
|Plain chocolate||2 Ounce (About 50 Gram)|
|Cocoa||1⁄2 Ounce (About 15 Gram)|
1) Grease two baking trays.
2) Cream the butter or margarine with the sugar until very soft, light and fluffy.
3) Gradually add the egg, beating continuously.
4) Divide the creamed mixture into two portions of approximately 250 g/9 oz and 150 g/5 oz.
5) Work 100 g/4 oz of the flour into the smaller portion.
6) Break the chocolate into pieces and place in a bowl over a saucepan of hot water.
7) Heat gently, stirring occasionally, until the chocolate has melted.
8) Sift the cocoa and the remaining flour into a bowl, then work these dry ingredients into the larger portion of creamed mixture, together with the melted chocolate.
9) Divide the plain dough into six and roll each piece into a sausage shape, 35 cm/14 in long, on a lightly floured board.
10) Divide the chocolate flavoured dough into approximately two thirds and one third.
11) Divide the smaller portion into five and roll each piece into a sausage shape in the same manner as the plain dough.
12) Place a plain and chocolate flavoured roll side by side, then arrange the remaining rolls on top of these, alternating the colours to form a chequerboard.
13) Roll the remaining chocolate flavoured dough into a rectangle measuring 35 x 15 cm/14 x 6 in.
14) Wrap the dough carefully around the chequer rolls, placing the join on the underside.
15) Wrap the roll in cling film or foil and chill overnight in the refrigerator.
16) To finish, cut the roll into 5 mm/1/4 in slices and place the slices at intervals on the prepared baking trays.
17) Bake in a moderately hot oven (200 C, 400 F, gas 6) for 10-12 minutes, or until darkened in colour and cooked.
18) Remove the hot biscuits from the trays and transfer them to a wire rack to cool completely.