1. Mix the flour, carob powder and sugar together in a bowl. Rub the margarine into the mixture and knead to form a soft dough.
2. Roll to 1/4 inch (5 mm) thick and cut into 3 by 1 inch (7.5 cm by 2.5 cm) rectangles.
3. Brush with egg. Sprinkle over 2 oz (50 g) finely chopped hazelnuts. Bake for 20 minutes at Mark 3 (160°C) 325°F..