Sift dry ingredients into a bowl. Rub in
margarine. Stir in herbs, cheese and egg yolk. Press mixture firmly
together with hand. Knead gently on lightly floured surface until
smooth. Cover and refrigerate for half an hour.
Roll dough between sheets of greaseproof
paper until 3mm thick. Cut dough into 4cm squares. Place cut cookies
about 2cm apart onto greased oven trays. Bake in moderately hot oven
for about 10 minutes or until lightly browned. Cool on wire rack.