The picture you saw was probably in one of Harold_V's posts. His was actually more gold shot than cornflakes.
Cornflakes are made by melting the metal, then slowly pouring it directly into water in a tall, metal container. You'll end up with a wide variety of shapes ranging from large, flattened things that truly look like cornflakes, to rounder blobs, long, thin, stringy things, etc. Cornflakes are made to maximize the surface area to volume ratio so digestions are faster and more complete. They also produce some very interesting shapes that can be used in jewelry.
Several things you can try are to get you water cold with some ice. Stir the water just before you pour. Alternately, you can build a simple propeller type stir bar on a shaft chucked in a drill and stir while pouring. GSP has given information on this technique. If you can't stir, pour the gold in a circle around the container of water so you're not pouring right in one spot. The hot metal can create a shaft of steam as it falls and molten metal can reach the bottom. Pour in a slow, steady stream. You'll still have to play with pouring height to obtain the results you want.
Shot is melted in a dish or crucible just as with cornflakes, but the metal is then poured into a shotting flask positioned just above the water. Shot is used by jewelers when they create their own gold alloys. Here, the goal is compact, rounded shapes with a low surface area to volume ratio. The shotting flask is a melting dish with a hole drilled in the bottom. It is then seasoned with a layer of borax just as a normal melting dish. The shotting flask is heated as the metal is being melted. The molten metal is poured into the shotting flask and it drops through the hole right into the water directly below it. There are other tricks and modifications on this basic technique that you can find by searching.
Dave
