1. Heat oven to 200 degrees F. Line 2 large baking sheets with wax paper. In large bowl, combine egg whites and sugar. Place bowl over pot of gently simmering water, and whisk constantly until sugar dissolves and egg mixture feels warm to touch, about 5 minutes.
2. Remove bowl from water bath, and with mixer on high, beat in extract, if desired. Continue beating until very stiff peaks form, about 8 minutes. Spoon mixture into large resealable plastic bag, and snip off one corner.
3. Pipe swan shapes onto prepared baking sheets. Sprinkle bottom half with blue sugar crystals. Place slivered almonds into swans for beaks, chocolate morsels for eyes. Bake until crisp throughout, about 55 minutes. Cool completely.