A cake with money in it won't break the bank, nor will it break a tooth as long as everyone knows to search for the hidden coins. A money cake is a Greek New Year tradition commonly called vassilopita, but money might also be added to a Mardi Gras king cake, or baked into a child's birthday cake. Kids and adults alike will enjoy the thrill of the treasure hunt as they search each sweet bite for a monetary surprise. You can bake a single coin into the cake or several -- just be sure to scrub them clean first.
Scrub the coins clean with hot, soapy water and a toothbrush. Select the cleanest coins you can find, preferably newly minted coins that haven't changed hands many times. Toothpaste also works well for cleaning coins, particularly if it contains baking soda, which acts as a micro-abrasive for scrubbing away grime.
Wrap each coin tightly in a 2-by-2-inch square of foil. Handle the foil carefully to avoid tearing it.
Prepare the cake batter. Spray a cake pan with non-stick baking spray or grease it with shortening and dust it with flour. Pour the cake batter to fill the pan 1/2 to 2/3 full.
Place the foil-wrapped coins on top of the cake batter, arranging them evenly across the cake if using multiple coins. Do not press the coins down into the batter. The weight of the coins will cause them to settle, and the cake will rise up to cover the coins. When using only one coin, stand the coin upright in the batter so there's less chance of cutting into a coin as you slice the cake.
Bake the cake according to your recipe. Remove it from the oven and let it cool completely before removing it from the pan.
Decorate the cake with frosting as desired. Coins might show through along the sides of the cake, so frosting is especially important for completely concealing them.