Oil a 9-by-13-inch baking sheet, and set aside. Combine sugar and 2 tablespoons water in a heavy-bottomed saucepan. Cook over low heat until sugar is dissolved. Cover pan, and bring to a boil. Leave cover on until condensation washes down insides of pan. Turn heat to medium and cook, swirling pan occasionally, until sugar turns amber in color and registers 320 degrees.on a candy thermometer. Quickly stir in almonds, and pour mixture onto prepared baking sheet. Spread with back of a metal spoon until thin. Allow to cool completely, and break into pieces, reserving some larger ones for garnish.
Scoop frozen yogurt or ice cream into wine or dessert glasses. Sprinkle with brittle, and garnish with a large shard. Drizzle amaretto over top if desired.