Mix all the ingredients, excluding the egg yolk, margarine and some of the cheese. Divide it into 10 balls and arrange them in a buttered and floured tray, flattening them just a bit.
Make a small indentation in the middle of each, smear with egg and put a little margarine on each.
Next, sprinkle with cheese. Bake in a preheated 392°F (200 °C) oven for about 20 min.