In the bowl of an electric mixer cream the softened butter at low speed for 1 hour, or until it is almost white.
Add the confectioners’ sugar 1 tablespoon at a time, the egg yolk, and the orange-flavored liqueur and mix until combined.
Blend in the flour and almonds, 1/2 cup at a time, to form a soft dough. If the dough seems sticky, chill it, wrapped in wax paper, for 1 hour.
Form the dough into 1-1/2-inch balls and press 1 clove into each ball. Put the balls on baking sheets and bake them in the preheated oven for 15 minutes, or until they are pale golden. Transfer the cookies to a rack, let them cool for 2 minutes. Remove the cloves and dredge them in sifted confectioners’ sugar.
VariationsDrizzle some rose water or a little orange liqueur over the cookies when they come out of the oven.