Remove rind from bacon, fry until golden on both sides, chop finely.
Beat butter until creamy, add egg yolk, mix well.
Add grated cheese, mix well.
Add sifted flour and salt, mix to a firm dough; wrap in plastic wrap and refrigerate 30 minutes.
Roll dough out on a lightly floured surface to 1/8 inch thick.
Cut into rounds with a 1 1/2 inch fluted cutter.
Put rounds on greased oven trays, sprinkle with bacon and extra cheese. Bake in moderate oven 10 - 12 minutes or until golden.
Allow to cool on a wire rack.
