These cake eggs are a gorgeous treat that also make a delicious April Fool's Day prank. The great thing about this idea is that you can customize the cake to be any flavor or color that you like.
Since the eggshells are smaller than cupcakes, you should use the moistest cake recipe you can find so they don't dry out while cooking.
Preheat your oven to 350°F. Make holes in the top of each egg using a corkscrew. The hole will have to be large enough to pipe in the cake batter. Save the eggs to use in something later.
Than, rinse out each eggshell. In a bowl of salted water, soak the eggshells for at least 30 minutes. Add more salt if they don't sink enough and make sure the eggshells are filled with the saltwater. Remove eggshells, rinse quickly in running water, shake out any water from inside, and then place on a plate covered with paper towels.
Prepare a muffin tin. Make a small aluminum foil nest in each hole, with an indentation in the middle so the eggs will be able to sit up. Fill a piping bag with tip or sandwich bag with cake batter. If using a sandwich bag, cut one tip. Place eggs in a Dixie cup or egg cup. Fill carefully with cake batter to two-thirds full.
Place filled eggs into muffin tin.
Bake cake eggs for 20 minutes and emove from oven and clean off any excess cake from the top of the eggs. Do this gently with a butter knife and damp paper towel or dish towel.
Serve as a fun April Fool's Day surprise or a spring-y Easter treat.