Preheat oven to Gas Mark 7/425°F/220°C. Put the grated cheese into a mixing bowl. Sift the flour with the baking powder and paprika into the cheese. Cut the butter into small pieces and rub into the flour and cheese with your fingertips. Add the egg yolks and mix with a wooden spoon to a stiff dough. Gather into a ball, press out with your hands on a floured board and roll out to about ½ in. (1 cm) thick. Cut into small biscuits with a 2 in. (5 cm) cutter or the rim of a glass. Place on a large ungreased baking sheet. Bake at the top of the oven for 8-12 minutes until light golden brown. Cool before removing from the baking sheet.