Things You'll Need
Pot of boiling water
In many cultures, baking a coin into a cake is part of religious festivals. Both the Portuguese and the Greeks bake King's Cakes for some holidays, and whoever is lucky enough to get a slice of the cake that contains a coin is thought to have good luck. But the logistics of baking a cake with money in it can be a bit tricky, and so the baker must use caution when preparing cakes of this type.
Choose your coin. A freshly minted coin is best, as it will have less accumulated grime. If you can't get to the bank to get a shiny new coin, you can place an older coin in boiling water to kill any surface bacteria and scrub with a toothbrush to remove grime. You may also boil the coin to sanitize it, and then wrap it in tinfoil prior to placing it in the cake.
Pour the cake batter into the pan and place it in the oven.
Remove the cake from the oven halfway through the baking time (the time will vary depending on your cake recipe). Push the coin into the partially set cake batter, smoothing over the insertion site to mask the point of entry. This will ensure the coin stays suspended in the cake, rather than settling towards the top or bottom of the cake where it might be easily seen, thus spoiling the surprise for your diners.
Make sure to place the coin halfway between the center and the outer edge of the pan, in order to prevent your knife from hitting it as you slice.
Return the cake to the oven and allow it to finish its baking time, removing it from the oven when a toothpick inserted into the cake comes out clean.
Invert the cake onto a cooling rack. Frost and consume within one day for best taste.
Never use paper money in a cake, only metal coins. Paper money can contain dyes, threads and other components that will transfer unpleasant flavors into the cake.
Always warn all your guests that there is a coin in the cake to prevent choking, and make sure children are supervised as they eat their cake.