Line 2 or 3 baking sheets with cooking parchment. Beat the egg whites in a deep bowl until stiff; lightly fold in the almonds & sugar & add a few drops of almond extract. Spoon the mixture into a pastry bag fitted with a large rosette tube & pipe it onto the baking sheets in small rosetts & S shapes, leaving about an inch between each. Decorate the petits fours with candied cherries, strips of angelica, silver shot, nuts, or candied violets. Bake in the center of a preheated oven at 350 about 20 minutes, until golden brown.