Gather your ingredients and prepare a baking sheet by lining it with parchment paper, or greasing very well. A marble slab comes in handy and helps the drops cool quickly.
Combine the ingredients, except for powdered sugar or cornstarch, in a heavy-bottomed pot or saucepan. Cook to hard crack stage, about 300°F, whisking every now and then in order to check the color and consistency. This may take between 15-20 minutes, or longer depending on the pan and stove. Test by dropping a little from a spoon into a bowl of ice water. If it cracks, it's ready. If it's chewy, cook for a few more minutes. Remove from the heat. Be careful not to let it burn - the temperature rises quickly at the end.
Let the mixture cool slightly. Drop onto baking sheet into rounds. Allow to cool completely.
Once cool, dust with the powdered sugar or cornstarch. Store in an airtight container in a cool, dry place away from any moisture. (Moisture will cause them to stick together.) Alternatively, they can be dusted and wrapped individually in small pieces of waxed or parchment paper.
Can be stored for up to a year in an airtight container in a cool, dry place.